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CVE-2026-52929 Linux CVE debrief

CVE-2026-52929 is a HIGH-severity vulnerability in the Linux kernel, with a CVSS score of 7.5. The vulnerability was resolved by fully rolling back denied add-stream state in the SCTP stream. When ADD_OUT_STREAMS is denied, SCTP only shrinks the queued chunks and then lowers outcnt, leaving removed stream metadata behind. This can cause a null-pointer dereference in the scheduler get path when a later re-add reuses a stale ext. The fix involves tearing down the removed stream state, unscheduling the current scheduler state, dropping the removed stream ext state, and rescheduling the remaining streams.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-24
Original CVE updated
2026-07-08
Advisory published
2026-06-24
Advisory updated
2026-07-08

Who should care

Linux kernel users and administrators should be aware of this vulnerability and take steps to patch their systems. This vulnerability can be exploited remotely, and its exploitation can result in a denial of service. Users of Linux distributions that include the affected kernel versions should prioritize patching.

Technical summary

The Linux kernel vulnerability CVE-2026-52929 involves a fix for a stream add-out denial issue in the SCTP stream. When ADD_OUT_STREAMS is denied, the kernel only partially rolls back the changes, leaving behind removed stream metadata. This can lead to a null-pointer dereference when the stream is re-added later. The fix involves a complete rollback of the denied add-stream state, ensuring that scheduler-private RR/FC/PRIO lists remain consistent.

Defensive priority

High priority should be given to patching this vulnerability, as it can be exploited remotely and can result in a denial of service. Linux kernel users and administrators should prioritize patching their systems to prevent potential exploitation.

Recommended defensive actions

  • Patch the Linux kernel to the latest version that includes the fix for CVE-2026-52929.
  • Review and update Linux distribution packages to ensure the patched kernel version is installed.
  • Perform a thorough inventory of Linux kernel versions in use and prioritize patching based on risk and exposure.
  • Monitor Linux kernel logs for potential exploitation attempts.
  • Implement compensating controls, such as network segmentation and access controls, to limit the attack surface.

Evidence notes

The CVE-2026-52929 vulnerability was published on June 24, 2026, and modified on June 28, 2026. The vulnerability has a CVSS score of 7.5 and is classified as HIGH severity. The fix involves a complete rollback of the denied add-stream state, ensuring that scheduler-private RR/FC/PRIO lists remain consistent.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-52929 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-52929

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

  • CVE-2026-52929 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-52929

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

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/0cd2dc6dce8ca47212cd306ccd52eb315ef3cf85

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

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/1c6773b8c081509dcd5cd2954f2b02c50c00f151

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

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/39dc2b0eb5371a669ebc9ec6072b9184eac95418

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

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/7dd9a42b044aad2dbe037db1c1e2943582485b44

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

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/9662eb0401518f0b4681f10e7fbf688f504f24cf

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

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/a5f8a90ac9f77c678a9781c0a464b635e0d63e49

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

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/a6724b7b812ac8793514a1d5938db5d9d29ae725

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

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.