PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-46087 Linux CVE debrief

A memory leak vulnerability exists in the Linux kernel's DAMON (Data Access MONitor) statistics subsystem. When damon_start() fails during damon_stat_start() execution, the DAMON context allocated by damon_stat_build_ctx() is not properly destroyed, resulting in a memory leak. Additionally, the stale damon_stat_context pointer persists and will be overwritten on subsequent enable attempts, rendering the original allocation permanently unreachable. This vulnerability affects kernel memory management integrity and could contribute to resource exhaustion under specific error conditions. The issue has been resolved by ensuring proper cleanup of the DAMON context and resetting the global pointer when damon_start() fails.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-27
Original CVE updated
2026-06-25
Advisory published
2026-05-27
Advisory updated
2026-06-25

Who should care

Linux kernel administrators and developers utilizing DAMON (Data Access MONitor) for memory access pattern monitoring; organizations running memory-constrained systems where kernel memory leaks could contribute to resource exhaustion; security teams tracking kernel memory integrity issues.

Technical summary

The vulnerability occurs in mm/damon/stat.c where damon_stat_start() allocates a DAMON context via damon_stat_build_ctx() but fails to clean up when damon_start() subsequently fails. The missing cleanup leaves the allocated context leaked and the global damon_stat_context pointer stale. On the next enable attempt, this stale pointer is overwritten without freeing the original allocation, causing permanent memory leakage. The fix implements proper destruction of the DAMON context and resets the global pointer when damon_start() returns an error, ensuring consistent memory management state.

Defensive priority

medium

Recommended defensive actions

  • Apply kernel patches from the referenced stable tree commits to affected systems
  • Monitor kernel memory usage on systems utilizing DAMON statistics features
  • Review system logs for damon_start() failures that may indicate trigger conditions
  • Validate kernel version against patched releases in stable trees

Evidence notes

The vulnerability description indicates a memory leak in mm/damon/stat when damon_start() fails, with the fix ensuring proper context destruction and pointer reset. Three kernel.org stable tree commits are referenced as resolution sources.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-46087 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-46087

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

  • CVE-2026-46087 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46087

    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/50bc1d7e0f3bb6932c8dc5da0907eead0790176b

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

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/8a62c58411cbd748d7aeab0e5b0963e33ff47a7a

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

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/e04ed278d25bf15769800bf6e35c6737f137186f

    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.