CVE-2026-31911 abort() in libpcap before 1.10.7 on an invalid BPF opcode
A crafted BPF filter program can cause libpcap to call abort(), terminating the process and causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-31911?
CVE-2026-31911 is a medium-severity denial of service vulnerability in The Tcpdump Group libpcap, published on 5 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
libpcap BPF interpreter calls abort() if it encounters a BPF instruction that has an invalid opcode. In particular uncommon use cases a crafted filter program can terminate the OS process.
Weakness: CWE-617
Which versions are affected by CVE-2026-31911?
How do I fix CVE-2026-31911?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-31911 being exploited?
There is no known exploitation of CVE-2026-31911 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-31911, AZL-99732, AZL-99930, BELL-CVE-2026-31911, DEBIAN-CVE-2026-31911, ECHO-a302-f1dc-85d5 and 2 more.