# CVE-2026-42144: CImg Library: Integer overflow in PNM size check bypasses memory guard (_load_pnm)

> Integer overflow in CImg library allows heap buffer overflow via crafted PNM files, potentially leading to code execution or denial of service.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 May 2026
- **Updated:** 5 May 2026
- **Also known as:** DEBIAN-CVE-2026-42144, GHSA-4663-63fm-44gc, UBUNTU-CVE-2026-42144

## What is CVE-2026-42144?

CVE-2026-42144 is a medium-severity vulnerability in GreycLab CImg, published on 4 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

CImg Library is a C++ library for image processing. Prior to commit 4ca26bc, there is an integer overflow vulnerability in the W*H*D size computation inside _load_pnm() that can bypass the memory allocation guard. A crafted PNM/PGM/PPM file with large dimension values causes the overflow to wrap around, allocating an undersized buffer and potentially triggering a heap buffer overflow. Any application using CImg to load untrusted image files is affected. This issue has been patched via commit 4ca26bc.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-42144?


## How do I fix CVE-2026-42144?

Apply the vendor's patch.

## Is CVE-2026-42144 being exploited?

There is no known exploitation of CVE-2026-42144 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42144 and fix it if it is affected.

What it is: CVE-2026-42144 is a medium-severity vulnerability in GreycLab CImg, published on 4 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-42144 in the wild and no public exploit code.

Affected product: GreycLab CImg. 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-2026-42144/ (Markdown: https://insights.sbomify.com/CVE-2026-42144/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42144
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42144
- OSV: https://osv.dev/vulnerability/CVE-2026-42144

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42144/
Summaries are generated and may contain mistakes; the official description above is the record.