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CVE-2026-43199 Linux CVE debrief

A 'scheduling while atomic' bug was fixed in the Linux kernel's mlx5e IPsec MAC address query. The issue arose from mlx5_query_mac_address() being called in atomic context, which could sleep. The fix involves using ether_addr_copy() to directly get the local MAC address from netdev->dev_addr. This change prevents potential 'scheduling while atomic' issues in the Linux kernel's mlx5e IPsec MAC address query, ensuring more reliable and secure network operations. Linux kernel developers and maintainers should assess exposure and apply the patch if necessary.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-06
Original CVE updated
2026-10-21
Advisory published
2026-05-06
Advisory updated
2026-10-21

Who should care

Linux kernel developers and maintainers, network security teams, and Linux distribution maintainers should assess exposure and apply the patch if necessary. These stakeholders are crucial in ensuring the Linux kernel's security and reliability, and their prompt action can prevent potential 'scheduling while atomic' issues in the mlx5e IPsec MAC address query.

Why it matters

A 'scheduling while atomic' bug was fixed in the Linux kernel's mlx5e IPsec MAC address query. Linux kernel developers and maintainers should assess exposure and apply the patch if necessary.

  • Verify and apply patches to prevent potential 'scheduling while atomic' issues in the Linux kernel.
  • Monitor Linux kernel security updates for related vulnerabilities.
  • Review network configurations to ensure IPsec MAC address queries are properly handled.

Technical summary

The bug was caused by mlx5_query_mac_address() being called in atomic context, which could sleep. The fix involves using ether_addr_copy() to directly get the local MAC address from netdev->dev_addr, preventing potential 'scheduling while atomic' issues in the Linux kernel's mlx5e IPsec MAC address query. This change ensures more reliable and secure network operations by avoiding the sleeping call and resolving the bug. Linux kernel developers and maintainers should assess exposure and apply the patch if necessary.

Defensive priority

Medium

Recommended defensive actions

  • Review and apply the patch to fix the 'scheduling while atomic' bug in the Linux kernel's mlx5e IPsec MAC address query.
  • Verify that the Linux kernel version is up-to-date with the fix.
  • Monitor the Linux kernel for any related security updates.
  • Assess exposure and apply the patch if necessary.
  • Review network configurations to ensure IPsec MAC address queries are properly handled.
  • Verify and apply patches to prevent potential 'scheduling while atomic' issues in the Linux kernel.
  • Monitor Linux kernel security updates for related vulnerabilities.

Evidence notes

The CVE record and source item provide details on the bug and its fix in the Linux kernel. The bug was in the mlx5e IPsec MAC address query, which could cause a 'scheduling while atomic' issue. The fix replaces mlx5_query_mac_address() with ether_addr_copy() to get the local MAC address directly from netdev->dev_addr, avoiding the sleeping call and resolving the bug. This information is based on the CVE record and source item, which provide a comprehensive overview of the vulnerability and its resolution.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-43199 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-43199

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-43199 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-43199

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • net/mlx5e: Fix "scheduling while atomic" in IPsec MAC address query

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/43xxx/CVE-2026-43199.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/5efde07521309274f26727860774614cbc187242

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/e1407fb7c337373dfaaae2445d828b0b9ae26a29

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/57957bc7f1865778ec9b1618e15515feb6df7eb4

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/546de94e41e92e1f7dc6213615fb7c794d05db98

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/859380694f434597407632c29f30fdb5e763e6cc

    Supplemental source

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.