Microsoft’s short public note that “Azure Linux includes this open‑source library and is therefore potentially affected” is an accurate, product‑scoped attestation — but it is
not a categorical guarantee that no other Microsoft product includes the same vulnerable kernel code. Azure Linux is the only Microsoft product Microsoft has publicly attested to include the implicated upstream component so far, yet any Microsoft artifact that ships a Linux kernel build with the drm/msm driver could also be a carrier until it is inspected and attested or independently verified.
Background / Overview
CVE-2025-38410 is a Linux kernel fix in the drm/msm DRM driver that corrects a resource/fence handling defect in the submit error path. The defect is in upstream kernel driver source (drivers/gpu/drm/msm or closely related msm display code) and the upstream patch ensures cleanup of fence objects or prevents double‑free / leak conditions during error unwinds. Because the code lives in the Linux kernel tree, any product or distribution that ships a kernel build containing that driver — and that kernel revision predates the upstream fix — can be potentially affected.
Microsoft’s Security Response Center (MSRC) entry for this CVE states that Azure Linux “includes this open‑source library and is therefore potentially affected,” and also notes Microsoft began publishing machine‑readable CSAF/VEX attestations beginning in October 2025 and will update the CVE mapping if additional Microsoft products are found to ship the component. That wording is precise: it reports the outcome of Microsoft’s inventory work to date and identifies the Microsoft product(s) Microsoft has verified — not an all‑products exclusion.
Why Microsoft named Azure Linux — and what that actually means
Microsoft’s VEX/CSAF rollout began with Azure Linux images as a pragmatic first step to provide deterministic, machine‑readable attestations for product‑level exposure. Azure Linux is Microsoft’s curated family of cloud OS images and kernel builds for Azure VM images; because Microsoft builds and maintains those Linux images, it can perform an artifact‑level inspection and state whether a given upstream component is present. When MSRC lists Azure Linux as including the implicated open‑source code, that is an authoritative signal for Azure Linux customers to triage and patch.
However, the key operational nuance is that this statement is an attestation
for Azure Linux only. Absence of a product name in Microsoft’s VEX feed or the MSRC advisory is
absence of attestation, not proof of absence. In other words, Microsoft’s public mapping confirms what Microsoft has found and verified so far, and Microsoft has committed to updating the CVE/VEX entries if further products are discovered to ship the same kernel component. Security teams should treat MSRC’s Azure Linux attestation as authoritative for that product family and still verify other Microsoft artifacts they run.
Technical anatomy: why this vulnerability matters beyond a single product label
The vulnerable code is part of the Linux kernel DRM driver stack targeting Qualcomm SoC platforms (the msm DRM/disp/DPU areas). That means exposure is a function of two independent facts:
- Whether the kernel binary shipped with a product or image actually includes the drm/msm driver (or related msm modules). Many server‑focused x86_64 kernels simply do not enable Qualcomm SoC drivers by default, while broad or SoC‑targeted kernel builds will.
- Whether runtime access to DRM device nodes (/dev/dri/*) or the specific driver ioctls is available to untrusted or unprivileged processes. If device nodes are exposed to untrusted containers, CI runners, or user sessions (compositors like Xwayland/Wayland), the local attack surface increases.
Because the driver is upstream kernel code, any product that ships a kernel built with CONFIG_DRM_MSM enabled (either compiled-in or as a module) and uses a kernel revision prior to the upstream fix is, in principle, potentially affected. That includes, but is not limited to:
- Azure Linux images that Microsoft has already attested.
- Any Microsoft‑provided kernel artifacts built for ARM/Qualcomm targets or broad configuration kernels that include msm. Examples to check: the WSL2 kernel binary (where Microsoft ships a kernel for WSL2), linux-azure kernels for specific VM families, Marketplace/curated images, IoT/appliance images, and internal test or partner builds.
Therefore, the short operational answer to the question "Is Azure Linux the only Microsoft product that includes this open‑source library and is therefore potentially affected?" is: No — Azure Linux is the only Microsoft product Microsoft has publicly attested to include the library so far, but other Microsoft artifacts could include the same kernel code depending on their kernel configuration and build provenance. Microsoft’s statement is authoritative for Azure Linux, but it does not preclude other artifacts from being carriers until those artifacts are inspected.
How to verify exposure for Microsoft‑provided artifacts (practical steps)
If your organization runs Microsoft‑provided images or artifacts, do not rely solely on Microsoft’s current product mapping. Instead, perform artifact‑level verification using the procedures below. These are short, practical checks that can be automated and run across fleets.
Quick checks on a running Linux image
- Confirm the running kernel version: uname -a.
- Check for the msm DRM module: lsmod | grep msm.
- Inspect installed modules: find /lib/modules/$(uname -r) -type f -name 'msm' -print.
- Check kernel config for driver selection: zgrep -i 'CONFIG_DRM_MSM' /boot/config-$(uname -r) or grep -i 'CONFIG_DRM_MSM' /lib/modules/$(uname -r)/build/.config.
- Look for DRM device nodes and their permissions: ls -l /dev/dri/* and evaluate group access or container mounts.
For offline images or unbootable artifacts
- Mount the image filesystem and inspect /lib/modules and /boot/config* for MSM references.
- Extract initramfs or kernel image, and search the compiled modules for msm.
- Check packaged kernel changelogs for the upstream commit IDs that map to the fix.
How to map kernel commits precisely
Do not assume kernel version numbers alone prove presence or absence of a fix: match vendor package changelogs or the kernel build’s included upstream commit IDs to the upstream stable commit(s) that implement the fix. This is the most reliable verification method. Public trackers such as NVD and distribution security trackers list the upstream commits and the stable branches the fix landed in — use those commit IDs to validate your kernel build.
Recommended immediate actions (prioritized checklist)
- Confirm Microsoft’s current advisory status for the specific Microsoft products you run. Treat MSRC’s Azure Linux attestation as authoritative for Azure Linux images.
- Inventory kernels and modules across your estate using the checks above (lsmod, find /lib/modules, zgrep CONFIG_DRM_MSM). Automate this where possible and feed results into your asset database.
- Patch promptly if any kernel image includes drm/msm and the kernel revision predates the upstream fix: install the vendor/distribution kernel update that contains the upstream commit and reboot. For custom kernels, cherry‑pick the upstream stable commit(s) and rebuild.
- If you cannot patch immediately, apply compensating controls: restrict access to DRM device nodes (/dev/dri/*) via udev rules or group membership, avoid mounting DRM device nodes into untrusted containers, and harden container runtimes to disallow device passthrough.
- Increase telemetry and monitoring for kernel oops traces referencing DRM/msm call frames and problematic function names; add relevant SIEM rules and alerts.
Risk model and who should care most
This defect is primarily an
availability / robustness issue: it can cause kernel oops, driver crashes, or host instability. That makes it particularly relevant for:
- Multi‑tenant cloud hosts, container/CI runners, and virtual desktop infrastructure (VDI) where a single host crash impacts many tenants.
- Embedded devices and vendor kernels (Android OEM kernels, SoC vendor trees) that often lag upstream and represent the long tail of unpatched devices.
- Any environment that intentionally exposes DRM device nodes to untrusted workloads (containers with device passthrough, GPU device plugins).
For most Microsoft x86_64 server workloads that do not include Qualcomm SoC drivers in their kernels, practical exposure will be low. That explains why Microsoft’s immediate mapping identifies Azure Linux (their curated image family) rather than, for example, the typical WSL kernel on x86 desktops — but the only way to be certain is artifact‑level inspection.
Cross‑checks and independent confirmation
Independent sources corroborate the technical scope and remediation approach for kernel DRM driver CVEs:
- Public vulnerability trackers (NVD, distribution security trackers) list the CVE and provide upstream commit references; these are primary technical ground truth for the fix and affected kernel ranges.
- Distribution advisories (Debian, Ubuntu, Red Hat, Amazon Linux, etc. map the upstream commits to fixed package versions and provide patch timelines. These pages confirm the standard remediation path: install vendor kernel update and reboot.
- Microsoft’s MSRC VEX/CSAF attestation for Azure Linux is the authoritative vendor mapping for Microsoft products and is intended to be expanded over time as Microsoft inventories more artifacts. This attestation model is transparent and lets automation triage Microsoft‑owned images rapidly.
If any claim about other Microsoft products lacking the driver cannot be verified by direct inspection or by Microsoft’s published VEX/CSAF statements, those claims should be treated as unverified and the artifact should be inspected as described above.
Practical verification example (step‑by‑step)
- On a suspected image/VM, run: uname -a to get the kernel release.
- Check for modules: lsmod | grep msm. If present, the artifact likely includes the drm/msm driver.
- Inspect module files: find /lib/modules/$(uname -r) -type f -name 'msm' -print.
- Confirm kernel config: zgrep -i 'CONFIG_DRM_MSM' /boot/config-$(uname -r) or examine any shipped kernel .config.
- If module is present but you cannot confirm the upstream fix by kernel version alone: extract the kernel package changelog or compare the skb/commit IDs in /proc/version or vendor package metadata to the upstream stable commit IDs listed in public trackers. Use those commit IDs as the canonical check.
Unverifiable claims and cautionary notes
- Microsoft’s statement that Azure Linux “includes the open‑source library and is therefore potentially affected” is verifiable for Azure Linux, but any claim that no other Microsoft product contains the code is unverifiable until Microsoft publishes attestations for those products or you perform artifact checks yourself. Treat absence of Microsoft’s attestation as a gap in instrumentation, not proof of safety.
- Kernel version numbers are not a foolproof indicator of whether a fix is present because downstream backports can change the mapping. Always verify using upstream commit IDs or vendor changelogs.
- Long‑tail embedded devices and OEM vendor kernels are frequently the slowest to receive backports; if your supply chain includes such devices, engage vendors for patch timelines.
Longer‑term operational recommendations
- Integrate artifact‑level SBOM and VEX/CSAF ingestion into your vulnerability triage workflows so product‑level attestations (like Microsoft’s Azure Linux VEX) can automatically reduce triage noise — but always back that up with per‑artifact verification where business risk demands it.
- Maintain a concise, automated kernel inventory (uname, kernel .config, module list) for all managed images — this makes rapid triage of upstream kernel CVEs fast and repeatable.
- For environments that must remain online, consider limiting exposure by preventing untrusted code from opening /dev/dri device nodes and by avoiding device passthrough into untrusted containers or CI runners. These compensating controls reduce risk until you can deploy a patched kernel and reboot.
Conclusion
Microsoft’s MSRC advisory correctly and transparently identifies Azure Linux as the Microsoft product Microsoft has inspected and found to include the vulnerable DRM/msm kernel component; Azure Linux customers should act promptly on that attestation. However, that statement is an inventory result, not a proof that no other Microsoft product includes the same open‑source component. Any Microsoft artifact that ships a Linux kernel build with the drm/msm driver (or similarly broad kernel configuration) could be a carrier until it is inspected or Microsoft updates its VEX/CSAF mapping. Security teams should therefore:
- Treat Microsoft’s Azure Linux attestation as authoritative for Azure Linux.
- Run the artifact‑level verification steps above for other Microsoft images you operate (WSL kernels, linux‑azure kernels, Marketplace images, appliance/IoT images).
- Patch promptly where the driver is present and apply short‑term compensations where immediate patching is not possible.
This operational posture both respects Microsoft’s transparent VEX/CSAF rollout and acknowledges the technical reality that kernel code inclusion is an artifact‑level property that must be validated per image or product.
Source: MSRC
Security Update Guide - Microsoft Security Response Center