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PatchSiren cyber security CVE debrief

CVE-2026-23011 Linux CVE debrief

A vulnerability has been resolved in the Linux kernel, specifically in the ipv4: ip_gre module. The issue arises from the ability of team or bonding drivers to dynamically change their dev->needed_headroom and/or dev->hard_header_len, which can lead to a crash in the ipgre_header() function. This vulnerability affects users of the Linux kernel, particularly those using versions 3.10.1 to 6.19. The vulnerability was discovered through syzbot testing, which found multiple ways to crash the kernel in ipgre_header().

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 6.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-14
Original CVE updated
2026-07-28
Advisory published
2026-07-14
Advisory updated
2026-07-28

Who should care

Users of the Linux kernel, particularly those using versions 3.10.1 to 6.19, should be aware of this vulnerability and take steps to mitigate it. This includes reviewing the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Technical summary

The vulnerability is caused by the dynamic change of dev->needed_headroom and/or dev->hard_header_len by team or bonding drivers, which can lead to a crash in the ipgre_header() function. The issue has been resolved through a series of patches. Affected product deployments exist in managed environments and require an owner for follow-up. Review compensating controls for exposed systems while remediation is scheduled and verified.

Defensive priority

Medium

Recommended defensive actions

  • Apply patches from the Linux kernel repository
  • Update to the latest Linux kernel version
  • Monitor for changes in dev->needed_headroom and/or dev->hard_header_len
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The vulnerability was discovered through syzbot testing, which found multiple ways to crash the kernel in ipgre_header(). The issue has been resolved through a series of patches. This vulnerability affects users of the Linux kernel, particularly those using versions 3.10.1 to 6.19. The dynamic change of dev->needed_headroom and/or dev->hard_header_len by team or bonding drivers can lead to a crash in the ipgre_header() function. To verify, defenders should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-23011 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-23011

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

  • CVE-2026-23011 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-23011

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

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/06fe0801396a36cab865b34f666de1d65bc5ce8e

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/2ecf0aa7cc262472a9599cc51ba02ada0897a17a

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/554201ed0a8f4d32e719f42caeaeb2735a9ed6ca

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/8d5b6b2d79c1c22a5b0db1187a6439dff375a022

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/aa57bfea4674e6da8104fa3a37760a6f5f255dad

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/e67c577d89894811ce4dcd1a9ed29d8b63476667

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/eeb9a521de40c6fadccc12fa5205e5a1b364d5a8

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

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.