CVE-2026-123784
Fluxbox through 1.3.7 OS Command Injection via Style Background Values
Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme() that allows attackers to execute commands via crafted style background values. Attackers can embed shell metacharacters in background pixmap paths, random directories, or gradient texture text, which are concatenated unescaped into an fbsetbg command run via $SHELL -c when the style loads.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.5
Fluxbox through 1.3.7 OS Command Injection via Style Background Values
Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme() that allows attackers to execute commands via crafted style background values. Attackers can embed shell metacharacters in background pixmap paths, random directories, or gradient texture text, which are concatenated unescaped into an fbsetbg command run via $SHELL -c when the style loads.
- Record
CVE-2026-123784- CVSS 4.0
- 8.5 High
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-78
- Updated
- 2026-11-06
EUVDEUVD-2026-118302
8.5
Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme() that allows attackers to execute commands via crafted style background values. Attackers can embed shell metacharacters in background pixmap paths, random directories, or gradient texture text, which are concatenated unescaped into an fbsetbg command run via $SHELL -c when the style loads.
- Record
EUVD-2026-118302- CVSS 4.0
- 8.5 High
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-06
GitHub AdvisoriesGHSA-c5cr-c2wq-j45j
8.5
Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme(...
Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme() that allows attackers to execute commands via crafted style background values. Attackers can embed shell metacharacters in background pixmap paths, random directories, or gradient texture text, which are concatenated unescaped into an fbsetbg command run via $SHELL -c when the style loads.
- Record
GHSA-c5cr-c2wq-j45j- CVSS 4.0
- 8.5 High
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/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 - CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-78
- Updated
- 2026-11-06
NVD
8.5
Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme() that allows attackers to execute commands via crafted style background values. Attackers can embed shell metacharacters in background pixmap paths, random directories, or gradient texture text, which are concatenated unescaped into an fbsetbg command run via $SHELL -c when the style loads.
- Record
CVE-2026-123784- CVSS 4.0
- 8.5 High
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/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 - CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-78
- Updated
- 2026-11-06
OSV
8.5
Fluxbox through 1.3.7 OS Command Injection via Style Background Values
Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme() that allows attackers to execute commands via crafted style background values. Attackers can embed shell metacharacters in background pixmap paths, random directories, or gradient texture text, which are concatenated unescaped into an fbsetbg command run via $SHELL -c when the style loads.
- Record
CVE-2026-123784- CVSS 4.0
- 8.5 High
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-78
- Updated
- 2026-11-08
OSVDEBIAN-CVE-2026-123784
7.8
Fluxbox through 1.3.7 contains an OS command injection vulnerability in RootTheme::reconfigTheme() that allows attackers to execute commands via crafted style background values. Attackers can embed shell metacharacters in background pixmap paths, random directories, or gradient texture text, which are concatenated unescaped into an fbsetbg command run via $SHELL -c when the style loads.
- Record
DEBIAN-CVE-2026-123784- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-07
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| references | OSV | |
| affected, aliases, references | OSV | |
| published | EUVD, NVD | |
| published | EUVD | |
| references, severity, title | CVE List | |
| aliases, products, published, references | EUVD | |
| first indexed | GitHub Advisories |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-123784 is a high vulnerability (CVSS 8.5) in Fluxbox, published November 6, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.71%, the 53rd percentile. No source names a fixed version.
References
github.com/fluxbox/fluxbox/pull/89
github.com/fluxbox/fluxbox
github.com/fluxbox/fluxbox/commit/270bfbc28573037c9b8458488d193b219e33889f
github.com/fluxbox/fluxbox/blob/Release-1_3_7/src/RootTheme.cc
vulncheck.com/advisories/fluxbox-through-1.3.7-os-command-injection-via-style-background-values
nvd.nist.gov/vuln/detail/CVE-2026-123784
github.com/advisories/GHSA-c5cr-c2wq-j45j
github.com/CVEProject/cvelistV5/tree/main/cves/2026/123xxx/CVE-2026-123784.json
security-tracker.debian.org/tracker/CVE-2026-123784