pam_usb: Shell injection via device UUID and username in pamusb-conf and pamusb-agent
Key facts
- Attack vector
- Local
- Privileges required
- High
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-78.
Summary
pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.8.7, a crafted UUID such as $(id>/tmp/rce) in the config causes root RCE when pamusb-conf --reset-pads is run. A USB device with a crafted filesystem UUID (some controllers allow this) can inject the payload at --add-device time. Also, userName from the XML config is passed to os.system() in pamusb-agent, which invokes a shell. This vulnerability is fixed in 0.8.7.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA pam_usb (mcdope) Fixed in 0.8.7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-44712
More mcdope vulnerabilities
- TI-2026-35505 pam_usb: PAM_RHOST check skipped when deny_remote=false allows XDMCP authentication bypass CVSS 3.1HIGH 8.1
- TI-2026-32598 pam_usb: Symlink attacks on pad directory and pad files enable authentication bypass and root file corruption CVSS 3.1HIGH 7.9
- TI-2026-32596 pam_usb: PINENTRY_FALLBACK_APP environment variable allows arbitrary command execution CVSS 3.1HIGH 7.8
- TI-2026-32600 pam_usb: Command injection via $TMUX environment variable leads to RCE as root CVSS 3.1HIGH 8.8
- TI-2026-34849 pam_usb: deny_remote feature incorrectly classifies IPv4-mapped IPv6 remote connections as local CVSS 3.1HIGH 7.4
- TI-2026-34852 pam_usb: OTP pad authentication bypass via missing system pad check and uninitialized RNG buffer CVSS 3.1HIGH 7.1
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences