CVE-2024-46677: Azure Linux Attestation and Kernel GTP Risk

Microsoft’s brief CVE mapping for CVE‑2024‑46677 names the Linux kernel’s GTP implementation as the vulnerable component and explicitly states that Azure Linux includes the implicated open‑source library and is therefore potentially affected — but that product‑level attestation is precise in scope, not a categorical claim that no other Microsoft product could contain the same vulnerable code.

Background / Overview​

The vulnerability tracked as CVE‑2024‑46677 is a classic kernel robustness bug: a potential NULL pointer dereference in the Linux kernel’s GTP (GPRS Tunnelling Protocol) handling. The upstream fix changes gtp_encap_enable_socket() so that, when sockfd_lookup() fails, the function returns a proper error pointer rather than a bare NULL; callers had been checking only for error pointers and therefore could miss a NULL return, creating the risk of a dereference. This issue was discovered during code inspection and has been included in upstream kernel patch streams.
Why this matters operationally: a NULL pointer dereference in kernel context typically causes a crash (an Oops/panic), resulting in high availability impact for the host. Exploitation is generally local (requires the attacker to trigger the vulnerable code path on the host), but because the kernel executes at the highest privilege level, even a non‑privileged crash can be a critical denial‑of‑service for servers and appliances that rely on affected kernels. Multiple vulnerability trackers and distro scanners have ingested the CVE and the upstream patch data as part of standard remediation feeds.

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What Microsoft actually said (and why the wording matters)​

Microsoft’s Security Response Center (MSRC) entries for a number of third‑party/open‑source CVEs have followed the same form: a short, factual line such as “Azure Linux includes this open‑source library and is therefore potentially affected by this vulnerability,” plus a promise to update the CVE mapping if additional Microsoft products are identified as carriers. That text is procedural — it confirms Microsoft completed an inventory for the Azure Linux product family and found the upstream component present there. Microsoft also publicly committed to publishing machine‑readable CSAF/VEX attestations beginning in October 2025 to improve transparency.
It is critical tcorrectly:

• Authoritative for Azure Linux: The attestation is definitive for the Azure Linux distribution Microsoft audited. If you run Azure Linux images, treat them as in‑scope and follow Microsoft’s remediation recommendations.
• Not an exclusivity guarantee: The absence of an MSRC attestation naming other Microsoft products is not proof those products do not contain the vulnerable code. Microsoft explicitly states it will update the CVE/VEX mapping if additional affected products are discovered, which makes the attestation an evolving inventory statement rather than a global exclusion.

This distinction — attested presence vs exclusive presence — is the central point for customers and defenders evaluating exposure in mixed Microsoft/third‑party environments.

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Technical verification: what the public data shows​

To verify the technical facts of CVE‑2024‑46677 I checked the upstream kernel tracking (as aggregated by NVD and other vulnerability databases) and corroborated the change description against multiple independent vulnerability feeds and distro advisories.

• NVD’s summary and the associated technical description match the upstream patch rationale: callers expected error pointers, but the function could return NULL when sockfd_lookup() failed, so the upstream fix was to return an appropriate error pointer.
• Commercial and open vulnerability databases (Tenable, OSV, Wiz, Recorded Future and others) list the same description, the same affected kernel branches and the same remediation approach (backported stable commits). These independent aggregators all point back to the same upstream kernel commits or stable backports.

Taken together, the technical consensus is consistent: CVE‑2024‑46677 is a medium‑severity availability impact, fixed upstream, and present in Linux kernel branches used by modern distributions until those branches picked up the stable backports.

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Is Azure Linux the only Microsoft product that includes the vulnerable library?​

Short answer: No — not necessarily. Azure Linux is the only Microsoft product Microsoft has publicly attested to include the implicated upstream kernel component for this CVE at the time of the advisory, but that attestation is product‑scoped and not a demonstration that other Microsoft artifacts do not include the same code.
Why that matters in practice:

• Microsoft ships many distinct artifacts that are built from or embed Linux kernels or Linux‑based components: Azure Marketplace VM images, managed node images for Kubernetes (AKS node images), the Azure kernel packages used by cloud services, WSL/WSL2 kernels, container base images published by Microsoft, partner or appliance images, and internal service images. Each artifact is assembled from a particular kernel version and build configuration; whether it contains the vulnerable gtp code depends on which kernel commits and which CONFIG options were used in that specific build.
• The presence of a file or driver in an upstream kernel tree does not automatically mean every artifact built by a vendor contains it. Kernel features are often enabled or disabled by CONFIG flags, and distributors backport or drop patches selectively.
• Microsoft’s wording therefore conveys that Azure Linux was inventory‑checked and found to contain the relevant upstream code; other Microsoft artifacts remain “not yet attested” rather than “proven not affected.”

This exact nuance is repeatedly emphasized in vulnerability analysis and vendor attestation guidance: product‑scoped VEX/CSAF attestations are excellent for reducing false positives for the named product but do not replace per‑artifact verification across an enterprise’s Microsoft‑supplied images.

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Practical implications for administrators and defenders​

If you operate Microsoft‑supplied images or services, here are the concrete steps to determine and reduce exposure.

• Inventory your Microsoft artifacts and identify which ones run a Linux kernel (for example, Azure Linux ages, WSL2 kernels, Marketplace appliances, and curated container base images). Treat each artifact as a separate target for verification.
• For each artifact, determine the kernel version and the build configuration (CONFIG_* flags). If the kernel version falls into the affected ranges cited by upstream feeds (and the build includes the GTP driver), assume exposure until proven otherwise.
• If you run Azure Linux images, prioritize updating those images to the patched kernel versions Microsoft published, since the MSRC attestation confirms they include the implicated component.
• For other Microsoft artifacts (WSL, AKS node images, Marketplace images):
• Obtain the SBOMs or package manifests where available.
• Inspect kernel packages inside the images (for example, rpm/dpkg package metadata or uname + kernel config).
• If you cannot obtain SBOMs, perform image scanning (container or VM) to list kernel package versions and detect presence of the gtp module.
• Apply vendor or upstream kernel security updates and patches where appropriate. If you maintain custom images, rebuild them against patched kernel packages or apply vendor‑approved backports.

These steps combine vendor guidance with standard vulnerability management hygiene: assume uncertainty for un‑attested artifacts, confirm with concrete artifacts (SBOMs, package manifests, kernel configs), and remediate where the presence of the code is verified.

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Why the attestation model is still useful — and where it falls short​

Microsoft’s product‑scoped attestations (Azure Linux first) are a meaningful improvement over silence: they give customers a starting point to prioritize remediation and reduce the window of confusion when dozens of third‑party advisories appear. The October 2025 rollout of machine‑readable VEX/CSAF attestations is a practical step to let automation ingest vendor mappings and act quickly.
But there are three important caveats:

• Attestations are only as useful as their coverage. If a vendor only attests a single product (e.g., Azure Linux) and does not yet publish attestations for other artifacts, defenders must still perform artifact‑level verification for other Microsoft images they run.
• The build‑time configuration of kernels matters. A kernel that includes the gtp source files might still produce builds that omit the gtp module depending on CONFIG options. Conversely, a kernel package built with the gtp feature will be affected even if other kernels are not. This variability is why per‑artifact checks are required.
• Timeliness and updates: Microsoft promises to update CVE/VEX records if additional products are identified, but until such an update appears, customers cannot assume “no other products are affected.” Treat “no attestation” as an unresolved inventory question, not an all‑clear.

Multiple independent vulnerability trackers and distro advisories echo this operational model: vendor attestations narrow the field but do not eliminate the need for artifact inspection and automated SBOM/image scanning.

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Example scenarios: where the vulnerable code might appear beyond Azure Linux​

• WSL/WSL2 kernels distributed by Microsoft: WSL kernels are Microsoft‑packaged kernel images. If they were built from kernel branches including the vulnerable commit and the gtp feature was enabled, those kernels could be affected. Check the published WSL kernel version and configuration.
• Azure Marketplace VM images and AKS node images: Marketplace images and managed node images are distinct artifacts. Some Marketplace images use distribution kernels;ed kernels. Inventory these images and compare kernel versions against the fixed branches.
• Container base images published by Microsoft: Container images that include a Linux kernel are rarer (containers normally use the host kernel), but images that bundle userland networking daemons or kernel module utilities could still reference or load gtp‑related userland tools; the main exposure remains kernel builds themselves. Image scanning and SBOM inspection are the right tools here.
• Internal Microsoft services and appliances (not publicly attested): large vendors sometimes incorporate upstream code into specialized internal builds. Only an explicit MSRC VEX update or SBOM disclosure will confirm those artifacts’ status.

In short: every artifact that could contain or run the vulnerable kernel code is a candidate for verification.

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Recommended remediation checklist (operational playbook)​

• For Azure Linux instances (highest priority):
• Apply Microsoft’s kernel security updates as published in the MSRC advisory and update the image to the patched kernel. Microsoft’s attestation confirms Azure Linux is in‑scope.
• For WSL2, AKS nodes, Marketplace images, and other Microsoft artifacts:
• Query image metadata, package versions, and kernel configs to determine the kernel version and whether gtp support is enabled.
• If package metadata is not available, boot a representative instance in an isolated environment and inspect the kernel package versions and /proc/config.gz or /boot/config‑* files.
• If the kernel version is in an affected branch and gtp support is present, schedule updates or rebuilds to use patched kernels.
• For third‑party and custom images that were built from Microsoft base images:
• Rebuild against updated base images or update kernel packages in base images and re‑deploy.
• For detection and monitoring:
• Add checks to your vulnerability management systems to flag kernel versions listed by upstream trackers as affected by CVE‑2024‑46677. Correlate those finds with MSRC attestations to prioritize Azure Linux pipelines.

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Risks, limitations, and remaining uncertainties​

• Exploitability: while CVE‑2024‑46677 is a local NULL pointer dereference (so the attacker must be able to invoke the code on the target host), such flaws are reliable ways to disrupt availability. There is no public, credible evidence of widespread exploitation for this specific CVE at the time of writing, but availability impacts deserve prompt remedial
• Vendor coverage: Microsoft’s VEX/CSAF program materially improves clarity, but the rollout is incremental. Until Microsoft publishes attestations for additional artifacts, defenders must perform artifact‑level checks for Microsoft images that are not Azure Linux images.
• Upstream vs packaged timelines: different distros and vendors pick up upstream patches at different cadences. An upstream kernel commit may be fixed quickly in mainline but take longer to appear in a specific distribution’s stable security kernel package; track your vendor’s security advisories and stable‑branch backports in parallel with upstream notifications.

When vendor attestations and upstream patch timelines differ, the safest path for critical infrastructure is to assume exposure until the artifact has been verified and patched.

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Bottom line and guidance for Microsoft customers​

• If you run Azure Linux images: treat Microsoft’s attestation as an authoritative signal that your Azure Linux images are potentially affected and should be updated following Microsoft’s guidance.
• If you run other Microsoft images (WSL2, AKS nodes, Marketplace VMs, container images, or vendor appliances): do not assume you are safe simply because Microsoft has not yet named those artifacts in a VEX/CSAF attestation. Perform artifact‑level verification: check kernel versions, kernel config flags, and package manifests; obtain SBOMs where available.
• Use automation: add kernel version and package checks for the affected releases to your vulnerability scanners, and correlate those signals with MSRC attestations to prioritize triage and remediation across heterogeneous fleets.

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Final assessment: strengths and risks of Microsoft’s approach​

Strengths

• Microsoft’s decision to publish machine‑readable VEX/CSAF attestations (starting with Azure Linux) is a positive step toward transparency and automation of vendor mappings. That commitment reduces ambiguity for customers of the attested product and accelerates remediation prioritization.
• The attestation provides a clear, immediate remediation priority for Azure Linux users and reduces the time customers spend chasing down whether the vendor audited a given product artifact.

Risks and limitations

• Product‑scoped attestations can create a false sense of security for operators who assume “not listed = not affected.” In complex, multi‑artifact environments that include many Microsoft‑supplied images, that assumption is unsafe. Microsoft’s explicit promise to update CVE mappings helps, but it is not a substitute for local verification.
• The speed of VEX/CSAF adoption and the depth of artifact coverage will determine how useful these attestations are in practice. Until the vendor attests a broad set of artifacts, defenders must retain artifact‑level detection and remediation controls.

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Microsoft’s MSRC attestation that “Azure Linux includes the implicated open‑source library and is therefore potentially affected” gives Azure Linux customers the immediate signal they need for prioritization; however, it does not prove exclusivity. Organizations running Microsoft images beyond Azure Linux should treat the attestation as authoritative for Azure Linux only and must verify other Microsoft artifacts by inspecting kernels, SBOMs, or package metadata. CVE‑2024‑46677 itself is a medium‑severity NULL pointer dereference in the Linux kernel’s GTP code that has been fixed upstream; apply patched kernels and perform per‑artifact checks to close any remaining blind spots.

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Source: MSRC Security Update Guide - Microsoft Security Response Center