CVE-2026-6554
infinte loop in libpcap before 1.10.7
- Published
- Updated
- Reserved
- Assigned by
- Tcpdump
Description
libpcap BPF interpreter treats the offset in the 'ja L' BPF instruction as a signed integer to implement looping via backward jumps, but it does not limit the number of loop iterations. A crafted filter program or the 'protochain' primitive used on a crafted network packet can cause the interpreter to loop infinitely.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| TcpdumpCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Awaiting Analysis | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.44% · top 62% of all CVEs (5 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
Affected products
- affected < 1.10.7
What to do
Solution: Upgrade to libpcap 1.10.7.
Workaround: Do not use filter programs that have been compiled outside of libpcap. Build libpcap without the 'protochain' primitive support.
Exploitation: Functional exploits exist for both attack vectors.
References (2)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-6554)Record last updated .