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PatchSiren cyber security CVE debrief

CVE-2026-11623 tmux CVE debrief

CVE-2026-11623 is a use after free vulnerability in tmux up to 3.6a. The vulnerability is located in the image_free function of image.c and requires local access with high complexity to exploit. The vulnerability has a CVSS score of 1.1 and is considered low severity. The exploit has been publicly disclosed and can be used. Upgrading to version 3.7-rc addresses this issue with the patch fc6d94a9f8a593bd8b7031650802084385d4ee03.

Vendor
tmux
Product
tmux
CVSS
LOW 1.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-09
Advisory published
2026-06-09
Advisory updated
2026-06-09

Who should care

Users of tmux up to version 3.6a should be aware of this vulnerability and take steps to upgrade to a patched version.

Technical summary

The vulnerability is a use after free issue in the image_free function of image.c in tmux up to 3.6a. This requires local access and has high complexity, making it difficult to exploit.

Defensive priority

Low

Recommended defensive actions

  • Upgrade to tmux version 3.7-rc or later.
  • Apply the patch fc6d94a9f8a593bd8b7031650802084385d4ee03.

Evidence notes

The CVE record and details were sourced from [cve-org](https://www.cve.org/CVERecord?id=CVE-2026-11623) and [nvd](https://nvd.nist.gov/vuln/detail/CVE-2026-11623).

Sources and references

Verified primary and authoritative sources

  • CVE-2026-11623 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-11623

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

  • CVE-2026-11623 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-11623

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

Supplemental references

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.