The Linux kernel vulnerability tracked as CVE‑2024‑58093 — a PCI/ASPM (PCI Express Active State Power Management) bug that can lead to use‑after‑free crashes during certain hot‑unplug sequences — has been publicly fixed upstream and widely patched by Linux distributors. Microsoft’s Security Response Center (MSRC) has published a product‑level attestation saying that Azure Linux includes the affected open‑source component and is therefore potentially affected, but that attestation does not mean Azure Linux is the only Microsoft product that could contain the same vulnerable code. In practical terms, any Microsoft product or image that ships a Linux kernel build (or a kernel‑based artifact) must be treated as an unverified artifact until you confirm the kernel version and whether the vendor backported the upstream fix.
CVE‑2024‑58093 is a correctness bug in the Linux kernel's PCI/ASPM handling. The upstream description explains that a change intended to prevent a use‑after‑free in multi‑function device (MFD) cases inadvertently freed a pcie_link_state structure too early when a PCIe switch had MFD on the upstream port; that left remaining downstream ports with pointers to freed memory and produced kernel crashes (general protection faults) particularly noticeable during hot‑unplug sequences. The Linux kernel CVE team and stable‑branch maintainers tracked the regression, and fixes were applied and backported into the stable branches.
The bug was introduced by a set of upstream commits and later corrected by a subsequent stable fix. Distributors and downstream vendors have since issued advisories, and multiple Linux distributions — including enterprise and cloud images — have published kernel updates addressing the flaw. That makes the vulnerability primarily a kernel‑level correctness flaw that affects systems whose kernel builds include the affected commit range and have the relevant ASPM code compiled in.
Put another way: Microsoft has said “Azure Linux includes this open‑source library and is therefore potentially affected.” That is factually correct and operationally useful — it tells Azure customers that Microsoft‑controlled Azure Linux artifacts were found to include the upstream code in question and therefore should be remediated. However, it does not logically prove that Microsoft’s other Linux kernels or kernel‑based images are free of the same code. The absence of a VEX attestation for a product is absence of attestation, not proof of absence.
CVE‑2024‑58093 is a reminder of two operational realities: first, that vendor attestations are valuable but often incremental; and second, that kernel bugs become a supply‑chain problem because the same upstream component may be embedded across many product families and images. For defenders, the practical, defensible posture is simple: treat Azure Linux as a confirmed hit (patch immediately), but also run a short artifact inventory for WSL2 kernels, Azure images, AKS nodes, and any Microsoft‑published kernel binary you use — then patch or mitigate those artifacts on the same timetable. (msrc.microsoft.com)
Conclusion: Azure Linux is the only Microsoft product Microsoft has publicly attested as including the affected open‑source library for CVE‑2024‑58093 at the moment of the advisory, but it is not the only Microsoft product that could contain the vulnerable kernel code. The correct operational response is immediate remediation of Azure Linux artifacts and a short, prioritized verification sweep of all Microsoft‑supplied kernel artifacts you operate — patch the kernels or apply short‑term mitigations, and verify fixes have been applied. (msrc.microsoft.com)
Source: MSRC Security Update Guide - Microsoft Security Response Center
Background / Overview
CVE‑2024‑58093 is a correctness bug in the Linux kernel's PCI/ASPM handling. The upstream description explains that a change intended to prevent a use‑after‑free in multi‑function device (MFD) cases inadvertently freed a pcie_link_state structure too early when a PCIe switch had MFD on the upstream port; that left remaining downstream ports with pointers to freed memory and produced kernel crashes (general protection faults) particularly noticeable during hot‑unplug sequences. The Linux kernel CVE team and stable‑branch maintainers tracked the regression, and fixes were applied and backported into the stable branches.The bug was introduced by a set of upstream commits and later corrected by a subsequent stable fix. Distributors and downstream vendors have since issued advisories, and multiple Linux distributions — including enterprise and cloud images — have published kernel updates addressing the flaw. That makes the vulnerability primarily a kernel‑level correctness flaw that affects systems whose kernel builds include the affected commit range and have the relevant ASPM code compiled in.
What Microsoft actually said — reading the MSRC attestation carefully
Microsoft’s advisory language for CVE entries follows its CSAF/VEX attestation model. In the advisory text you quoted, MSRC explains that Azure Linux is known to include the relevant upstream component and is therefore potentially affected, and that Microsoft began publishing CSAF/VEX attestations in October 2025 as part of a phased rollout of product‑level inventory data. Microsoft also explicitly promises to update the CVE/VEX mapping if it discovers additional Microsoft products that ship the same upstream component. This phrasing is deliberate: it is an authoritative confirmation for Azure Linux artifacts at the time of publication, not a declaration that no other Microsoft product could ever include the same code. (msrc.microsoft.com)Put another way: Microsoft has said “Azure Linux includes this open‑source library and is therefore potentially affected.” That is factually correct and operationally useful — it tells Azure customers that Microsoft‑controlled Azure Linux artifacts were found to include the upstream code in question and therefore should be remediated. However, it does not logically prove that Microsoft’s other Linux kernels or kernel‑based images are free of the same code. The absence of a VEX attestation for a product is absence of attestation, not proof of absence.
Short answer to the user’s question
- Strictly literal (what Microsoft published): Yes — Azure Linux is the only Microsoft product Microsoft has publicly attested as including the implicated open‑source library for this CVE at the time of that advisory. (msrc.microsoft.com)
- Practical/operational (what you must assume for defense): No — Azure Linux is not necessarily the only Microsoft product that could be affected. Any Microsoft product or service that ships, maintains, or distributes Linux kernel builds — for example, the WSL2 kernel, Azure‑tuned kernels used in some VM SKUs or images, AKS node images, and other kernel artifacts Microsoft publishes — could include the same upstream component depending on kernel version, backports and build configuration. You must verify each artifact individually.
Why this distinction matters for defenders
VEX/CSAF attestation provides a machine‑readable, high‑fidelity inventory statement for a named product family. When MSRC marks Azure Linux as “Known Affected” or “Potentially Affected,” that is useful to automation and prioritization. But large vendors rarely begin such a rollout with an exhaustive inventory of every binary image, kernel build, device driver bundle, and Marketplace image they publish. The phased approach — start with one product family, prove the process, then expand — is common because exhaustive scanning of millions of artifacts is resource‑intensive. The operational consequence for customers: treat Azure Linux as a definite hit and remediate it immediately, and treat other Microsoft artifacts as unverified until you (or Microsoft) confirm otherwise.Where the same vulnerable code could appear inside Microsoft’s ecosystem
Be explicit: any product that includes a Linux kernel binary or kernel‑based image can carry this bug if that kernel falls within the affected commit range and has the ASPM code enabled in its configuration. Examples to check:- Windows Subsystem for Linux (WSL2) — Microsoft publishes and maintains a WSL2 kernel tree used to build the WSL kernel images; that tree includes drivers under drivers/gpu/drm/amd and the generic PCI/ASPM code paths if enabled. You must check the WSL kernel version your Windows host uses and whether Microsoft’s WSL kernel release you have contains the upstream fix.
- Azure Marketplace images and Azure‑tuned kernels (often packaged as linux‑azure or similar) — some Azure VM SKUs run kernels Microsoft builds or tunes for Azure. Those artifacts can be different from the distribution vendor’s default kernel and therefore need per‑artifact verification.
- AKS node images and managed node pools — Kubernetes node images used by Azure Kubernetes Service sometimes include Azure‑maintained kernels or kernel packages; these must be checked and patched separately.
- Any other Microsoft‑published kernel binary (OEM images, specialized VMs, appliance images, etc.) — treat them as unverified until proven otherwise.
How to determine whether a particular host, image, or product is affected — an operational checklist
Below is a practical, step‑by‑step checklist you can run now. These checks are fast and definitive for a given host or image.- Inventory: Identify all hosts, cloud images, VM SKUs, and endpoints that run a Linux kernel you did not fully build and control (this includes VMs in Azure, WSL2 instances on Windows clients, container host nodes, and appliances).
- Determine kernel version and config: On each candidate Linux instance run:
- uname -r (reports kernel release)
- cat /proc/version (reports build info)
- zgrep CONFIG_PCIEASPM /boot/config-$(uname -r) or check the kernel config used to build the image (to know if ASPM code is compiled).
These tell you the exact kernel version and whether the ASPM code is present. If you cannot log into the image, check the image metadata or vendor advisory for kernel package version. - Map kernel version against upstream fixed commits and vendor advisories: Upstream lists the commits that introduced and fixed the regression and which stable branches received backports. The linux‑cve‑announce thread and NVD summarize the fix and the ranges. If your kernel version predates the fixed stable releases (or your vendor has not published a backport), consider it vulnerable.
- Check vendor advisories for your distribution or image: Look up the distro or image advisory (for example, Ubuntu, Red Hat, SUSE, Amazon Linux, Oracle Linux, and Microsoft’s Azure Linux VEX entries) to see whether the vendor claims “Fixed” or “Not Affected” for your exact image/kernel. Patch accordingly.
- For Windows hosts running WSL2: check the WSL kernel version locally with wsl --status and run wsl --update if required. Microsoft publishes WSL2 kernel releases and also ships updates via Windows Update or the Microsoft Store pipeline; updating the WSL kernel is a supported remediation path.
- For Azure customers using Microsoft images: check the Azure image SKU documentation, Azure Update/Advisory channels, and the MSRC VEX entries for the image to see whether Microsoft has published an attestation for that item; if not, treat it as unverified and apply the same kernel checks as above.
Practical mitigation and remediation options
Primary remediation: apply vendor/kernel updates. This is the recommended and definitive fix.- For distribution kernels: install the vendor’s kernel update package as published in the distro advisory (for example, the fixed kernels published by Ubuntu, Red Hat, SUSE, Amazon Linux, Oracle Linux, etc.). Patch timelines and package names vary by vendor — consult the vendor advisory and patch promptly.
- For Azure Linux customers: follow Microsoft’s guidance and apply the Azure Linux updates or new images Microsoft publishes. Because Microsoft has attested Azure Linux as including the component, treat Azure Linux images as a high‑priority remediation target. (msrc.microsoft.com)
- For WSL2 users: run wsl --update to obtain the latest WSL2 kernel, then restart WSL with wsl --shutdown and verify the new kernel with wsl --status. Microsoft’s WSL kernel releases are public; if you are managing many Windows endpoints, consider adopting a patching policy that includes WSL kernel updates.
- Disable or change ASPM behavior at boot time: the kernel boot parameter pcie_aspm=off or pcie_aspm.policy=performance will tell the kernel not to attempt ASPM transitions (or to avoid ASPM policy changes), which reduces the code paths that triggered the bug. Be aware that pcie_aspm semantics have changed across kernel versions and that disabling ASPM can increase power consumption or change device latency. Use this only as a short‑term mitigation while you plan the kernel update.
- Control ASPM at runtime: where available, change /sys/module/pcie_aspm/parameters/policy to “performance” (disables ASPM) or “default” to reduce risk; note the same caution about side effects applies.
- Apply host‑level containment: restrict physical hot‑plug/unplug operations in environments where those events are common (for example, maintenance windows on blade chassis) until kernels are updated; the bug was particularly visible during hot‑unplug sequences. This is operationally awkward but can be effective as a stopgap in sensitive environments.
How to prioritize remediation in the real world
Use a risk‑based approach:- Highest priority: cloud images and managed services you operate that Microsoft controls end‑to‑end (e.g., Azure Linux images you provision from Microsoft) — MSRC’s attestation marks these as confirmed carriers and should be remediated first. (msrc.microsoft.com)
- High priority: WSL2 on critical developer or CI/CD hosts that run untrusted workloads or build kernels/drivers — update the WSL kernel and instruct developers to run wsl --update.
- Medium priority: distribution kernels on internal VMs or on‑prem servers — patch according to vendor advisories (many distros have already published fixes).
- Lower priority: images and hosts that do not include the ASPM code (for example, kernels built with CONFIG_PCIEASPM disabled), or devices that lack PCIe root complexes using ASPM-sensitive devices — still verify and document the result.
Detection and monitoring: what to look for
This vulnerability is primarily a stability/use‑after‑free crash issue rather than a widely‑exploitable remote kernel compromise. Typical operational indicators include:- OOPs / kernel oops / general protection faults (GPFs) on PCIe hot‑unplug or ASPM policy changes recorded in dmesg or the system journal. These will often show stack traces in pcie_config_aspm_link or related PCI ASPM functions.
- KASAN use‑after‑free warnings if kernel memory sanitizer is enabled in debug builds — you’ll see slab‑use‑after‑free traces referencing pcie_config_aspm_link.
- Unexpected reboots or crashes correlated to device removal or power‑state changes on PCIe buses.
Verification: what “fixed” looks like
Upstream commit details and distro advisories list the commits or stable releases that contain the fix. The linux‑cve‑announce thread and NVD/OSV summaries contain the authoritative mapping of introduced and fixed commit ranges. After applying a vendor patch or installing a patched kernel image, confirm the kernel release is at or above the fixed version or that your vendor explicitly states the CVE is fixed for your package. Then reproduce the previously observed conditions (if safe to do so in a test environment) to verify the crash no longer occurs.The policy implications for cloud/enterprise customers
Microsoft’s VEX/CSAF rollout — beginning with Azure Linux in October 2025 — is an important step toward machine‑readable, vendor‑provided attestation of per‑product vulnerability status. That reduces noise and helps automation. But it is not, by itself, a replacement for artifact‑level verification where your environment relies on multiple Microsoft‑published artifacts (WSL kernels, Azure VM images, Marketplace appliances, etc.). Security teams should:- Treat MSRC VEX attestations as authoritative for the named product(s) and act on them immediately.
- Maintain an independent, automated inventory and kernel‑version scanning capability for images and hosts you run (including WSL hosts and Windows clients where WSL2 is deployed).
- Require that your patching program includes Microsoft‑published kernel artifacts as well as vendor distribution kernels so you don’t miss Microsoft‑maintained images that ship Linux kernels.
Actionable checklist you can run in the next 24–72 hours
- Query all Linux‑kernel‑bearing images and endpoints for kernel release (uname -r) and kernel config (zgrep CONFIG_PCIEASPM /boot/config-$(uname -r) or equivalent).
- For WSL2 endpoints, script wsl --status across your Windows estate (or instruct users) and schedule wsl --update where required.
- Compare kernel versions to vendor advisories and the upstream fix mapping (use linux‑cve‑announce and distro advisories).
- Patch Azure Linux images immediately if you consume them, according to Microsoft’s published updates and VEX attestations. (msrc.microsoft.com)
- If you cannot patch within the maintenance window, apply pcie_aspm=off or set /sys/module/pcie_aspm/parameters/policy to “performance” as a temporary mitigation — test first.
- Monitor logs for kernel oopses and KASAN warnings tied to pcie_aspm paths; escalate hosts exhibiting such traces.
Final analysis — strengths, risks, and what to expect next
Strengths- Microsoft’s new CSAF/VEX attestation model and the decision to start with Azure Linux gives customers a clear, machine‑readable signal for at least one major product family. That improves automation and reduces false positives for Azure customers.
- The kernel community and major distributors responded with fixes and backports; vendor advisories are available and most supported vendors have published patched kernel packages. That means definitive remediation is available for most mainstream deployments.
- MSRC’s attestation for Azure Linux is product‑scoped and not exhaustive. Customers who interpret the advisory to mean “only Azure Linux is affected” will be exposed if they run other Microsoft‑supplied kernel artifacts that include the vulnerable code. This is a communication and expectation management risk, not a technical error; defenders must act accordingly. (msrc.microsoft.com)
- Temporary mitigations (disabling ASPM) carry tangible operational tradeoffs — higher power usage, possible latency changes, and the risk of unintended side effects. They should only be used while scheduling the real fix.
- Microsoft will likely continue to expand its VEX/CSAF attestations to additional product families beyond Azure Linux. When they identify other Microsoft artifacts that include a given upstream component, Microsoft has committed to update the CVE/VEX mapping. Until then, customers must perform artifact‑level checks to be sure.
- Vendors will continue to publish backports and kernel package updates; prioritize patching based on exposure and the operational checklist above.
CVE‑2024‑58093 is a reminder of two operational realities: first, that vendor attestations are valuable but often incremental; and second, that kernel bugs become a supply‑chain problem because the same upstream component may be embedded across many product families and images. For defenders, the practical, defensible posture is simple: treat Azure Linux as a confirmed hit (patch immediately), but also run a short artifact inventory for WSL2 kernels, Azure images, AKS nodes, and any Microsoft‑published kernel binary you use — then patch or mitigate those artifacts on the same timetable. (msrc.microsoft.com)
Conclusion: Azure Linux is the only Microsoft product Microsoft has publicly attested as including the affected open‑source library for CVE‑2024‑58093 at the moment of the advisory, but it is not the only Microsoft product that could contain the vulnerable kernel code. The correct operational response is immediate remediation of Azure Linux artifacts and a short, prioritized verification sweep of all Microsoft‑supplied kernel artifacts you operate — patch the kernels or apply short‑term mitigations, and verify fixes have been applied. (msrc.microsoft.com)
Source: MSRC Security Update Guide - Microsoft Security Response Center
