CVE-2026-123785 json
Fluxbox through 1.3.7 Infinite Loop via Menu::updateMenu() Style Geometry
published 2026-11-06 2 d ago modified 2026-11-06 2 d ago also EUVD-2026-118303
- cvss
- 5.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 5%
- public exploits
- 0
- none known
Summary
Fluxbox through 1.3.7 contains an infinite loop vulnerability in Menu::updateMenu() in src/FbTk/Menu.cc that allows attackers to hang the window manager via crafted style geometry values. Attackers can supply a style with an oversized unbounded menu.titleHeight so the column loop never terminates, causing sustained CPU use and denial of service at startup.
Patch / fix
- github.com/fluxbox/fluxbox#90 pull request
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 d ago
Exploit prediction
0.17% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.8 | CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| CNA | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
| CNA | 4.0 | 6.8 | CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- fluxbox fluxbox
Classification
- Weakness
-
- CWE-835 Loop with Unreachable Exit Condition
References
-
github.com
/fluxbox/fluxbox/pull/90
issue-tracking, patch
-
github.com
/fluxbox/fluxbox
product
-
github.com
/fluxbox/fluxbox/blob/Release-1_3_7/src/FbTk/Menu.cc#L433-L448
technical-description
-
vulncheck.com
/advisories/fluxbox-through-1.3.7-infinite-loop-via-menu-updatemenu-style-geometry
third-party-advisory
Sources
- CVE List CVE-2026-123785
- NVD CVE-2026-123785
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