CVE-2026-123785 · Package
NO FIX YET
Fluxbox, a Linux window manager, loops forever in its menu update code when a style file sets an oversized menu title height. An attacker who gets a crafted style loaded can hang the window manager and cause a denial of service at startup.
first public Nov 6, 2026 · 1 source
Check it with your coding agent
It checks your repository and tells you if you’re affected, with the fix.
Only systems running Fluxbox 1.3.7 or earlier where a style file with a very large menu title height is loaded. Exposure depends on whether untrusted or third-party style files are used; systems that use the default style from a trusted source or run other window managers can skip it.
Not affected if default-style-only, other-window-manager
Who cares fluxbox, linux-desktop, window-manager
fluxbox -version or check the installed package version to see whether it is 1.3.7 or earliermenu.titleHeight to an unusually large valueNo fix yet, per the sources.
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.
This page as .md · .json · 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
NVD data is provided by NIST and is public domain. Posts quoted belong to their authors.
Are you affected?
Tell InfraStack what you run. It checks this one, and every next one, against your stack.
Ask from here. InfraStack checks the affected versions against your stack and answers in your inbox.
InfraStack checks the affected versions against your stack and answers in Slack, with the evidence and the fix.