Microsoft’s public attestation that “Azure Linux includes this open‑source library and is therefore potentially affected” is correct — but it is a scoped product-level statement, not a categorical guarantee that no other Microsoft product contains the vulnerable Protocol Buffers C++ implementation; Microsoft’s machine-readable VEX/CSAF record for CVE‑2024‑2410 explicitly lists Azure Linux and CBL Mariner product entries (and even a CBL‑Mariner package entry) as known carriers, and Microsoft says it will update the CVE if additional products are discovered. (msrc.microsoft.com)
CVE‑2024‑2410 is a use‑after‑free vulnerability in the Protocol Buffers (protobuf) C++ JSON parser: specifically, the JsonToBinaryStream() path can read bytes from a buffer chunk that has already been freed when input is presented as separated chunks rather than a single contiguous JSON buffer. The bug was introduced in the 4.22.0 cycle and fixed in the release that maps to protobuf 4.25.0 / tag v25.0. Upstream release notes and vulnerability records make this explicit. (github.com)
Security analysts and vulnerability databases give CVE‑2024‑2410 a high to critical impact rating (depending on the scoring source) and emphasize that the defect is exploitable when an application parses JSON from a stream broken into chunks — an input shape that appears in real networked or streaming parsers. That means any component that links the vulnerable protobuf C++ parsing code and exposes streaming JSON inputs may be at risk.
Microsoft’s natural‑language FAQ that appears on many MSRC vulnerability pages repeats the same point: for many open‑source components the company currently publishes product‑level attestations for Azure Linux as a distribution it actively inventories and maintains, and it will update CVE records if additional Microsoft products are identified as carriers. That FAQ also notes Microsoft’s broader program to publish machine‑readable CSAF/VEX attestations (the public roll‑out of that program is tied to late‑2025 activity). In short: Microsoft is telling customers two things at once — (a) “Azure Linux includes this component and is therefore potentially affected,” and (b) “we will expand this mapping if/when we find other Microsoft products that ship the same upstream component.”
In practical terms:
CVE‑2024‑2410 is a classic example of a widely reused open‑source component creating downstream risk: Microsoft has done the right thing by publicly mapping the problem for the Microsoft‑managed Linux distributions it controls, but defenders must complete the rest of the work — inventory, verification, and remediation — across their own fleets and any Microsoft artifacts they rely on.
Source: MSRC Security Update Guide - Microsoft Security Response Center
Background / Overview
CVE‑2024‑2410 is a use‑after‑free vulnerability in the Protocol Buffers (protobuf) C++ JSON parser: specifically, the JsonToBinaryStream() path can read bytes from a buffer chunk that has already been freed when input is presented as separated chunks rather than a single contiguous JSON buffer. The bug was introduced in the 4.22.0 cycle and fixed in the release that maps to protobuf 4.25.0 / tag v25.0. Upstream release notes and vulnerability records make this explicit. (github.com)Security analysts and vulnerability databases give CVE‑2024‑2410 a high to critical impact rating (depending on the scoring source) and emphasize that the defect is exploitable when an application parses JSON from a stream broken into chunks — an input shape that appears in real networked or streaming parsers. That means any component that links the vulnerable protobuf C++ parsing code and exposes streaming JSON inputs may be at risk.
The technical heart of the flaw
- What fails: JsonToBinaryStream() performs parsing that assumes lifetime and contiguity semantics that are invalid when input slices are processed in discrete allocations. A particular sequence of chunked inputs can trigger use‑after‑free when the parser refers to memory that the allocator has already returned. (github.com)
- Where it lives: the defect is in the core C++ protobuf library; language bindings that call into the C++ parser (or embed the C++ runtime) are the ones that inherit this risk. The upstream fix is part of the protobuf v25.0 release; downstream Linux distributions and product maintainers have been rolling that fix into their packaged protobuf builds. (github.com)
- Practical exploitability: the vulnerability does not require local privileges when the affected code is reachable via a networked parser; however, exploitation often depends on the target application exposing a JSON streaming path that uses the vulnerable API. Many applications will never exercise that code path, but many others — particularly streaming servers, telemetry ingestion, and some database connectors — might. Vulnerability scanners and defenders should therefore treat the presence of the vulnerable protobuf version as a meaningful signal but require further application‑level review to determine exploitability.
What Microsoft has said — and what that wording means
Microsoft’s Security Response Center has published a VEX/CSAF record for CVE‑2024‑2410 that maps affected Microsoft products and packages. That VEX record lists Azure Linux (Azure Linux 3.0) and CBL Mariner 2.0 in the product tree and shows subsequent revisions that add CBL‑Mariner package entries (for example, a mysql component was later mapped in CBL‑Mariner). The VEX metadata was updated as recently as February 18, 2026 in the published JSON, showing Microsoft’s ongoing product‑mapping activity. (msrc.microsoft.com)Microsoft’s natural‑language FAQ that appears on many MSRC vulnerability pages repeats the same point: for many open‑source components the company currently publishes product‑level attestations for Azure Linux as a distribution it actively inventories and maintains, and it will update CVE records if additional Microsoft products are identified as carriers. That FAQ also notes Microsoft’s broader program to publish machine‑readable CSAF/VEX attestations (the public roll‑out of that program is tied to late‑2025 activity). In short: Microsoft is telling customers two things at once — (a) “Azure Linux includes this component and is therefore potentially affected,” and (b) “we will expand this mapping if/when we find other Microsoft products that ship the same upstream component.”
Short answer to the question you asked
No — Azure Linux is not necessarily the only Microsoft product that could include the protobuf C++ runtime, and Microsoft’s VEX/CSAF record bears that out: the published VEX for CVE‑2024‑2410 already includes entries for Azure Linux and CBL Mariner, and Microsoft has recorded downstream package entries (for example, a MySQL package in CBL‑Mariner) as the product mapping evolved. Microsoft’s attestation that “Azure Linux includes this library and is therefore potentially affected” is authoritative for the product it names, but absence of a public attestation for other Microsoft SKUs is not proof they are unaffected — it often means they have not yet been inventory‑checked and published in the VEX. (msrc.microsoft.com)Evidence: what the VEX/CSAF and other sources show
- Microsoft VEX (machine‑readable): the MSRC VEX JSON for CVE‑2024‑2410 shows a product tree including Azure Linux 3.0 and CBL Mariner 2.0 and lists revision history where Microsoft added content such as “Added mysql to CBL‑Mariner 2.0.” That is direct, authoritative mapping data for Microsoft‑shipped Linux distributions and packages. (msrc.microsoft.com)
- Independent CVE/NVD and distribution advisories: the vulnerability description and fix (protobuf v25.0 / 4.25.0) are recorded in multiple independent sources (CIRCL/CVE records, Ubuntu advisories, and upstream release notes). These records confirm the vulnerability details and the upstream remediation version. This cross‑corroboration is important because Microsoft’s product attestation intentionally covers Microsoft products only — it does not replace the broader CVE/distribution ecosystem’s findings.
Why customers should not assume exclusivity
There are several practical reasons why the Azure Linux attestation should not be interpreted as a global Microsoft‑wide fix:- Microsoft ships many artifacts that can include third‑party libraries: cloud VM images and container base images, appliance images for Azure services, Linux kernels and userspace packages (CBL‑Mariner), developer tooling (vcpkg, Visual Studio components), and internal services. Any of those artifacts might carry a copy of protobuf depending on how they are built or packaged. The presence (or absence) of protobuf in other Microsoft products is an empirical question that requires an inventory check or SBOM mapping. Microsoft’s public VEX attestation is exactly that — an inventory result for the products Microsoft has scanned and chosen to publish so far. (msrc.microsoft.com)
- Downstream packaging and component substitution vary: different product teams or distributions may repackage upstream libraries at different times. A distribution that incorporated protobuf 4.22.x in mid‑2024 might be vulnerable until it updates to 4.25.0+, while another Microsoft product that never included the C++ JSON parsing path will not be exploitable even if protobuf is present. The nuance of "present" vs "reachable" vs "exploitable" is important when assessing risk. (github.com)
- Microsoft’s ongoing VEX program is incremental: the company’s CSAF/VEX roll‑out (publicized as starting in October 2025) means product mappings have become more visible — but they started from Azure Linux and CBL‑Mariner and are being expanded as Microsoft performs inventory work. Until a product shows up in MSRC’s published VEX as known_affected or not_affected, defenders should consider the product’s exposure unknown and proactively verify.
Practical, prioritized actions for defenders and administrators
If your organization uses Microsoft products or services — or runs customer workloads on Azure Linux / CBL Mariner — follow these steps. I list immediate actions first, then follow‑up actions.- Inventory: identify every Microsoft‑distributed artifact in your environment (VM images, container base image tags, CBL‑Mariner images, Azure Marketplace VM images, and any Microsoft agents) and query whether the artifact includes protobuf C++ (versions prior to 4.25.0). Use SBOMs where available.
- Consult MSRC VEX: review the MSRC VEX/CSAF JSON for CVE‑2024‑2410 to see product entries Microsoft has published (Azure Linux, CBL Mariner, and package details). Update your inventory checks against the VEX mapping. (msrc.microsoft.com)
- Patch or upgrade protobuf where possible: if you maintain an image or package that includes protobuf 4.22.0 ≤ version < 4.25.0, plan to upgrade to 4.25.0 or newer and test the change. Upstream protobuf v25.0 documents the fix. (github.com)
- Application‑level review: for any application using protobuf C++ that exposes JSON streaming input paths, perform a code review or run fuzzing / parsing tests that exercise chunked streaming inputs to determine whether the vulnerable JsonToBinaryStream() path is reachable. Not all uses of protobuf will exercise this API.
- Compensating controls: if you cannot upgrade immediately, consider limiting exposure by:
- rate‑limiting or filtering untrusted JSON streaming endpoints;
- adding WAF signatures to block specifically malformed chunked JSON patterns;
- isolating services that parse untrusted streaming JSON behind hardened proxies.
- Monitor MSRC and distribution advisories: subscribe to MSRC updates and distribution security advisories (CBL‑Mariner, Azure Linux patch announcements) and re‑check the VEX/CSAF mapping for updates to the CVE mapping. Microsoft has said it will update the CVE record if other products are found to ship the component. (msrc.microsoft.com)
How to verify whether a Microsoft artifact in your inventory is affected
- Check MSRC VEX/CSAF: for Microsoft‑shipped images and packages, MSRC’s machine‑readable VEX is authoritative for whatever products Microsoft has already scanned. Use the VEX JSON for automated cross‑referencing in your vulnerability management pipeline. (msrc.microsoft.com)
- Pull SBOMs or run file scans: if you have the VM image or container image in your registry, inspect it for protobuf binaries, headers, or package metadata and determine the shipped protobuf version. Tools such as distro package managers, SBOM exporters, or binary strings scans are appropriate.
- Use software composition analysis (SCA): SCA tooling can scan builds and packaged artifacts to find the presence and version of protobuf, and can be integrated into CI/CD to catch vulnerable versions before deployment.
- When in doubt, assume unknown = potential: treat Microsoft products that do not yet appear in the VEX mapping as “not yet checked” rather than “not affected,” and prioritize verification where those artifacts accept untrusted streaming JSON input.
Risk analysis — who should worry most?
- High risk: cloud‑facing services, telemetry ingestion endpoints, streaming parsers, or any component that accepts chunked JSON from untrusted sources and links in the C++ protobuf JSON parser. If such code paths are present in your Microsoft artifacts (for example, an Azure Linux image running a telemetry service that uses the C++ protobuf JSON streaming API), patching or mitigating is urgent.
- Medium risk: internal services that accept chunked JSON only from semi‑trusted sources, or components that use protobuf but only in a contiguous JSON parsing mode — these require application‑level verification to confirm whether the vulnerable path is reachable.
- Low risk: products that include protobuf only as a build‑time tool (protoc) or in language bindings that do not call the vulnerable C++ JsonToBinaryStream() path, or Microsoft artifacts that ship patched protobuf versions. Still, inventory and verification are recommended.
Why Microsoft chose Azure Linux as the first attested product — and what that implies
Microsoft’s published attestations have prioritized the operating system distribution they steward (Azure Linux / CBL‑Mariner) because those images are centrally built, patched, and distributed by Microsoft. Publishing VEX/CSAF for those images is a natural early win for transparency and customer security: it gives cloud customers immediate, machine‑readable mapping from a CVE to specific Azure Linux packages and versions. That does not mean Microsoft’s other product teams are exempt from the underlying supply‑chain risk — it simply reflects how Microsoft phased the inventory work. Expect to see additional Microsoft product mappings over time as the VEX program matures. (msrc.microsoft.com)What we still do not know (and where to be cautious)
- We cannot assume that every Microsoft product has been scanned; the absence of an MSRC attestation for a particular Microsoft SKU is not proof of non‑exposure. Organizations must perform their own artifact scans. (msrc.microsoft.com)
- Even if protobuf is present, the vulnerability may not be exploitable in a given product because the vulnerable API might not be used or might be compiled out; verifying the usage path is necessary to convert “present” into “exploitable.” (github.com)
- Some third‑party components and language bindings receive separate advisories (for example, Java, Python, Ruby variants of protobuf have distinct advisories). Ensure you track the language ecosystems your environment uses, because fixes and version numbers differ by language and packaging.
Timeline and vendor response (concise)
- May 3, 2024: CVE‑2024‑2410 publicly recorded and assigned to Protocol Buffers C++ JSON parser behavior. Upstream release notes document the fix in the release corresponding to 4.25.0 / tag v25.0. (github.com)
- 2024–2025: Linux distribution vendors and downstream packagers released updates; multiple distributors published advisories and patches mapping the CVE to their packages.
- 2024–2026: Microsoft published a VEX mapping for CVE‑2024‑2410 that includes Azure Linux and CBL‑Mariner entries and updated that mapping as it found additional Microsoft artifacts to enumerate (for example, adding MySQL package entries to CBL‑Mariner). Microsoft’s public FAQ reiterates that Azure Linux is a known affected Microsoft product and that MSRC will update the VEX if further products are identified. (msrc.microsoft.com)
Final analysis and guidance
Microsoft’s statement that Azure Linux includes this open‑source library and is therefore potentially affected is accurate and helpful for cloud customers using those images. However, it is not an exclusivity guarantee. The correct security posture for defenders is to assume “unknown until verified” for Microsoft artifacts that do not yet appear in MSRC’s published VEX mapping, and to actively inventory, scan, and remediate any instances of protobuf C++ versions < 4.25.0 in your software supply chain.In practical terms:
- Treat MSRC’s VEX as an authoritative starting point for Microsoft‑shipped artifacts (it names Azure Linux and CBL‑Mariner for CVE‑2024‑2410). (msrc.microsoft.com)
- Use SBOM and SCA tooling to find protobuf in your environment, map versions, and prioritize upgrades to the upstream fixed release (protobuf 4.25.0 / v25.0 or newer). (github.com)
- Conduct application‑level review of streaming JSON paths to determine whether the vulnerable JsonToBinaryStream() API is actually exercised; if it is, expedite remediation or apply compensating controls.
Quick checklist (for security teams)
- [ ] Pull the MSRC VEX JSON for CVE‑2024‑2410 and parse Microsoft product mappings. (msrc.microsoft.com)
- [ ] Run SCA / SBOM scanners against all Microsoft images and internal artifacts to find protobuf C++ versions.
- [ ] For any protobuf 4.22.0 ≤ version < 4.25.0: schedule an upgrade to 4.25.0+ or plan package updates from your vendor/distributor. (github.com)
- [ ] Audit code paths for streaming JSON parsing that may hit JsonToBinaryStream(); prioritize patching those services.
- [ ] Subscribe to MSRC and your distribution vendors for further VEX/CSAF updates and patches.
CVE‑2024‑2410 is a classic example of a widely reused open‑source component creating downstream risk: Microsoft has done the right thing by publicly mapping the problem for the Microsoft‑managed Linux distributions it controls, but defenders must complete the rest of the work — inventory, verification, and remediation — across their own fleets and any Microsoft artifacts they rely on.
Source: MSRC Security Update Guide - Microsoft Security Response Center
