# 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.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** Yes
- **Published:** 5 Sep 2026
- **Updated:** 8 Sep 2026
- **Also known as:** ALPINE-CVE-2026-31911, AZL-99732, AZL-99930, BELL-CVE-2026-31911, DEBIAN-CVE-2026-31911, ECHO-a302-f1dc-85d5, GHSA-r2j4-mj7w-mgg2, UBUNTU-CVE-2026-31911

## 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 (Reachable Assertion)

## Which versions are affected by CVE-2026-31911?


## How do I fix CVE-2026-31911?

Upgrade to a fixed version.

## Is CVE-2026-31911 being exploited?

There is no known exploitation of CVE-2026-31911 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31911 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-31911 in the wild and no public exploit code.

Affected product: The Tcpdump Group libpcap. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-31911/ (Markdown: https://insights.sbomify.com/CVE-2026-31911/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31911
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31911
- OSV: https://osv.dev/vulnerability/CVE-2026-31911

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31911/
Summaries are generated and may contain mistakes; the official description above is the record.