Always-Incorrect Control Flow Implementation in libseccomp - #VU139167
Published: July 22, 2026
Vulnerability identifier: #VU139167
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-670
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass intended seccomp restrictions.
The vulnerability exists due to a logic error in _db_tree_add() in libseccomp filter tree construction when merging multiple rules for the same syscall and the same 64-bit argument using SCMP_CMP_LT or SCMP_CMP_LE. A remote attacker can supply input that reaches a syscall argument range the policy was intended to deny to bypass intended seccomp restrictions.
The issue affects 64-bit architectures only and requires overlapping rules with the same high 32-bit comparison value, different low 32-bit values, and different actions.
Affected software
libseccomp
Remediation
Install security update from vendor's website.
libseccomp - update to 2.6.1