Double free in libseccomp - #VU139166
Published: July 22, 2026
Vulnerability identifier: #VU139166
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-415
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to double free in _bpf_append_blk() in src/gen_bpf.c when generating BPF filters from an extremely large seccomp rule set. A remote attacker can supply a specially crafted oversized seccomp profile to cause a denial of service.
The issue occurs during filter generation before the filter is loaded into the kernel, and exploitation requires an unusually large non-default rule set of roughly 66,000 rules.
Affected software
libseccomp
Remediation
Install security update from vendor's website.
libseccomp - update to 2.6.1