# CVE-2026-31912: OOBR in libpcap before 1.10.7

> A crafted BPF filter program in libpcap can cause out-of-bounds memory reads, potentially leading to information disclosure or 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-2026-31912, AZL-99741, AZL-99921, BELL-CVE-2026-31912, DEBIAN-CVE-2026-31912, ECHO-c577-82f0-747c, GHSA-5r9v-8527-q4jv, UBUNTU-CVE-2026-31912

## What is CVE-2026-31912?

CVE-2026-31912 is a medium-severity memory corruption 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 detects neither reaching the end of the filter program buffer due to lack of a return instruction nor executing a jump instruction with an offset that translates to a pointer outside of the buffer.  In particular uncommon use cases a crafted filter program can cause the interpreter to try reading the OS process memory in the 32GiB around the buffer on 64-bit architectures and in the entire address space on 32-bit architectures.

Weakness: CWE-823 (Use of Out-of-range Pointer Offset), CWE-1285 (Improper Validation of Specified Index, Position, or Offset in Input), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-31912?


## How do I fix CVE-2026-31912?

Upgrade to a fixed version.

## Is CVE-2026-31912 being exploited?

There is no known exploitation of CVE-2026-31912 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31912 and fix it if it is affected.

What it is: CVE-2026-31912 is a medium-severity memory corruption 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-2026-31912 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-2026-31912/ (Markdown: https://insights.sbomify.com/CVE-2026-31912/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31912
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31912
- OSV: https://osv.dev/vulnerability/CVE-2026-31912

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31912/
Summaries are generated and may contain mistakes; the official description above is the record.