# CVE-2026-5121: Libarchive: libarchive: arbitrary code execution via integer overflow in iso9660 image processing

> A remote attacker can achieve arbitrary code execution on 32-bit systems by exploiting an integer overflow in Libarchive's ISO9660 processing via a crafted image.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Mar 2026
- **Updated:** 14 Oct 2026
- **Also known as:** AZL-81504, CLSA-2026-1777365744, CLSA-2026-1777366496, DEBIAN-CVE-2026-5121, ECHO-fe78-e324-d857, GHSA-2vwv-vqpv-v8vc, MINI-q2gc-42gp-x2rr, UBUNTU-CVE-2026-5121

## What is CVE-2026-5121?

CVE-2026-5121 is a high-severity vulnerability in Libarchive Libarchive, published on 30 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in libarchive. On 32-bit systems, an integer overflow vulnerability exists in the zisofs block pointer allocation logic. A remote attacker can exploit this by providing a specially crafted ISO9660 image, which can lead to a heap buffer overflow. This could potentially allow for arbitrary code execution on the affected system.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-5121?

It affects 4 products.


Products: Libarchive Libarchive, Redhat Enterprise Linux, Redhat Hardened Images, Redhat Openshift Container Platform.

## How do I fix CVE-2026-5121?

Apply the vendor's patch.

## Is CVE-2026-5121 being exploited?

There is no known exploitation of CVE-2026-5121 in the wild and no public exploit code.

## Other vulnerabilities in Libarchive Libarchive

- [CVE-2024-37407](https://insights.sbomify.com/CVE-2024-37407/): Memory corruption in n/a (critical 9.1)
- [CVE-2016-1541](https://insights.sbomify.com/CVE-2016-1541/): Memory corruption in n/a (high 8.8)
- [CVE-2016-6250](https://insights.sbomify.com/CVE-2016-6250/): Integer overflow in n/a (high 8.6)
- [CVE-2025-5914](https://insights.sbomify.com/CVE-2025-5914/): Libarchive: double free at archive_read_format_rar_seek_data() in archive_read_support_format_rar.c (high 7.8)
- [CVE-2024-48957](https://insights.sbomify.com/CVE-2024-48957/): Memory corruption in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5121 and fix it if it is affected.

What it is: CVE-2026-5121 is a high-severity vulnerability in Libarchive Libarchive, published on 30 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-5121 in the wild and no public exploit code.

Affected product: Libarchive Libarchive. 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-2026-5121/ (Markdown: https://insights.sbomify.com/CVE-2026-5121/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5121
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5121
- OSV: https://osv.dev/vulnerability/CVE-2026-5121

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5121/
Summaries are generated and may contain mistakes; the official description above is the record.