Immediate
Before a patch is released, reduce exposure immediately and only allow trusted sources to reach the affected service.
root@hackertop:~/vulnfeed/CVE-2026-11623#
CVE-2026-11623
MEDIUM
CVE
⚠ Unpatched · Zero-day◉ PoC 公开
Lifecycle 4/7
tmux up to 3.6a image.c image_free use after free
LIFECYCLE
4.1
CVSS
Vulnerability Description
A vulnerability was found in tmux up to 3.6a. It has been classified as critical. This affects the function image_free of the file image.c. Upgrading to version 3.7-rc eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch fc6d94a9f8a593bd8b7031650802084385d4ee03 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.
Root Cause Analysis
CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
Impact: This is going to have an impact on confidentiality, integrity, and availability.
Exploit: The exploit is shared for download at gist.github.com. It is declared as proof-of-concept.
Countermeasure: Upgrading to version 3.7-rc eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch fc6d94a9f8a593bd8b7031650802084385d4ee03 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.
Impact: This is going to have an impact on confidentiality, integrity, and availability.
Exploit: The exploit is shared for download at gist.github.com. It is declared as proof-of-concept.
Countermeasure: Upgrading to version 3.7-rc eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch fc6d94a9f8a593bd8b7031650802084385d4ee03 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.
Validation (PoC/EXP) - Looking for Contributors
No public PoC yet
Public validation traces already exist. Community contributors can extend them with richer reproduction content.
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Mitigation Plan - Sorted by Priority
High
Enable extra access controls, WAF/ACL, or reverse-proxy rules for tmux.
High
Use logs and IOCs to hunt through production traffic and confirm whether exploitation traces already exist.
Medium
Keep this issue on the watch list and follow vendor advisories, rollback notices, and new variants.
Vulnerability Lifecycle - Click each stage to inspect details
The issue has entered HackerTop VulnFeed and is now being tracked by the community.
The vulnerability has been synchronized into the platform and entered the visible triage flow.
Initial impact validation is complete based on current disclosure, technical details, and public intelligence.
A public proof path already exists for reference.
No in-the-wild exploitation has been confirmed yet, but monitoring should continue.
No vendor patch is available yet. Apply temporary mitigations first.
Reduce exposure, restrict access, and inspect logs until a permanent fix is available.
4.1
CVSS
Temp Score
4.1
MEDIUM
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Metric Details
Attack Vector
Attack Vector
Network
Attack Complexity
Attack Complexity
Low
Privileges Required
Privileges Required
None
User Interaction
User Interaction
None
Confidentiality Impact
Confidentiality Impact
High
Integrity Impact
Integrity Impact
High
Availability Impact
Availability Impact
High
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CVE-2026-11623 · CVSS 4.1 · Active Threat
