Fluxbox through 1.3.7 contains an infinite loop vulnerability in Menu::updateMenu() in src/FbTk/Menu.cc that allows
Source GCVE Database
Not known to be exploited · CVSS 6.8 Medium.
Data as of 6 Nov 2026, 16:48 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 6.8 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 5.5 |
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 6 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| fluxboxfluxbox | Affected
| Fixed in– |
GitHubfluxboxpkg:github/fluxboxOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should monitor vendor advisories for updates addressing this vulnerability. Until a fix is released, avoid using untrusted style files that could trigger this condition.
Description
Fluxbox versions through 1.3.7 have an infinite loop vulnerability in the Menu::updateMenu() function. This flaw allows attackers to cause the window manager to hang by supplying a crafted style with an oversized unbounded menu.titleHeight, resulting in a non-terminating column loop. The attack leads to sustained CPU usage and denial of service during startup.
References
- nvd.nist.gov/vuln/detail/CVE-2026-123785 (opens in a new tab)
- github.com/fluxbox/fluxbox/pull/90 (opens in a new tab)
- github.com/fluxbox/fluxbox (opens in a new tab)
- github.com/fluxbox/fluxbox/blob/Release-1_3_7/src/FbTk/Menu.cc (opens in a new tab)
- vulncheck.com/advisories/fluxbox-through-1.3.7-infinite-loop-via-menu-updatemenu-style-geometry (opens in a new tab)