Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme() that allows
Source GCVE Database
Not known to be exploited · CVSS 8.5 High.
Data as of 6 Nov 2026, 16:50 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 8.5 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 7.8 |
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/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
Until a fix is available, avoid loading untrusted style files or background configurations that could be crafted to exploit this vulnerability.
Description
Fluxbox versions up to 1.3.7 have an OS command injection vulnerability in the RootTheme::reconfigTheme() function. This flaw allows attackers to execute arbitrary commands by crafting style background values that include shell metacharacters. These crafted values are concatenated without proper escaping into an fbsetbg command executed via the shell when the style loads.
References
- nvd.nist.gov/vuln/detail/CVE-2026-123784 (opens in a new tab)
- github.com/fluxbox/fluxbox/pull/89 (opens in a new tab)
- github.com/fluxbox/fluxbox/commit/270bfbc28573037c9b8458488d193b219e33889f (opens in a new tab)
- github.com/fluxbox/fluxbox (opens in a new tab)
- github.com/fluxbox/fluxbox/blob/Release-1_3_7/src/RootTheme.cc (opens in a new tab)
- vulncheck.com/advisories/fluxbox-through-1.3.7-os-command-injection-via-style-background-values (opens in a new tab)