PatchTheCVECVE-2026-6554: libpcap BPF interpreter treats the offset in the 'ja L' BPF instruction as a signed integer to implement loopi
37
Routine
HIGH 7.5REMOTE
CVE-2026-6554 is a high-severity flaw (CVSS 7.5) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.3% (top 77%) |
| CISA exploited list | No |
| Weakness | CWE-835 |
| Published | 2026-09-05 |
| Last modified | 2026-10-22 |
Publisher (CNA): Tcpdump Group
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Fedora 46 · wasmedge · FIXED · 0.18.1-1.fc46 · FEDORA-2026-4c27216e39 · source
sudo dnf upgrade --advisory=FEDORA-2026-4c27216e39
Debian 12 · libpcap · NO FIX YET
Debian 13 · libpcap · NO FIX YET
RHEL 10 · libpcap · NO FIX YET
RHEL 6 · libpcap · NO FIX YET
RHEL 7 · libpcap · NO FIX YET
RHEL 8 · libpcap · NO FIX YET
RHEL 9 · libpcap · NO FIX YET
Alpine 3.21 · libpcap · FIXED · libpcap-1.10.7-r0
apk add --upgrade libpcap
apk info -v libpcap
Alpine 3.22 · libpcap · FIXED · libpcap-1.10.7-r0
apk add --upgrade libpcap
apk info -v libpcap
Alpine 3.23 · libpcap · FIXED · libpcap-1.10.7-r0
apk add --upgrade libpcap
apk info -v libpcap
Alpine 3.24 · libpcap · FIXED · libpcap-1.10.7-r0
apk add --upgrade libpcap
apk info -v libpcap
sudo dnf update --advisory=ALAS2023-2026-3100
sudo yum update --advisory=ALAS2-2026-3927
Advisories and coverage
Official advisories
- Amazon Linux 2023 ALAS: ALAS2023-2026-3100 (important): libpcap 2026-09-29
- Amazon Linux 2 ALAS: ALAS2-2026-3927 (important): libpcap 2026-09-28
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Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.