CVE-2026-11623
CVE-2026-11623 is a medium-severity vulnerability with a CVSS 3.x base score of 4.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.
Key facts
- Severity: Medium (CVSS 3.x base score 4.5)
- CVSS v2: 3.5
- CVSS v4: 1.1
- EPSS exploit prediction: 0% (3rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-35297
- Weakness: CWE-119
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-11623?
- 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.
- How severe is CVE-2026-11623?
- CVE-2026-11623 has a CVSS 3.x base score of 4.5, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
- Is CVE-2026-11623 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-11623?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-11623 have an EU (EUVD) identifier?
- Yes. CVE-2026-11623 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35297.
- When was CVE-2026-11623 published?
- CVE-2026-11623 was published on 2026-06-09 and last updated on 2026-06-17.
References
- https://gist.github.com/XlabAITeam/f0d9952595f795129a3258ba73bbc3cb
- https://github.com/tmux/tmux/
- https://github.com/tmux/tmux/commit/fc6d94a9f8a593bd8b7031650802084385d4ee03
- https://github.com/tmux/tmux/releases/tag/3.7-rc
- https://vuldb.com/cve/CVE-2026-11623
- https://vuldb.com/submit/835623
- https://vuldb.com/vuln/369303
- https://vuldb.com/vuln/369303/cti
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- CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.