CVE-2026-55373

MEDIUMCVSS 6.2/10EPSS 0.11%

Last modified

CVE-2026-55373 is a medium-severity vulnerability rated 6.2/10 on the CVSS scale. OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. Versions prior to 3.2.10, 3.3.12, and 3.4.13 contain an infinite-loop vulnerability in SampleCountChannel. EPSS estimates a 0.11% chance of exploitation in the next 30 days.

Description

OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. Versions prior to 3.2.10, 3.3.12, and 3.4.13 contain an infinite-loop vulnerability in SampleCountChannel. The helper roundListSizeUp() rounds a sample-list size up to the next power of two using repeated unsigned left shifts, which terminates for normal values but fails for UINT_MAX: the sequence reaches 0x80000000, and the next left shift wraps the 32-bit value to 0. Because 0 remains less than UINT_MAX, the loop never progresses and never exits. The bug is reachable through public OpenEXRUtil APIs, either by editing the sample-count buffer through SampleCountChannel::Edit (whose destructor calls endEdit()) or by calling SampleCountChannel::set(x, y, UINT_MAX) on a valid pixel. This issue has been fixed in versions 3.2.10, 3.3.12, and 3.4.13.

Metrics

EPSS Probability
0.11%

1.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
AcademySoftwareFoundationopenexr< 3.2.10; >= 3.3.0, < 3.3.12; >= 3.4.0, < 3.4.13

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-55373?
OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. Versions prior to 3.2.10, 3.3.12, and 3.4.13 contain an infinite-loop vulnerability in SampleCountChannel. The helper roundListSizeUp() rounds a sample-list size up to the next power of two using repeated unsigned left shifts, which terminates for normal values but fails for UINT_MAX: the sequence reaches 0x80000000, and the next left shift wraps the 32-bit value to 0. Because 0 remains less than UINT_MAX, the loop never progresses and never exits. The bug is reachable through public OpenEXRUtil APIs, either by editing the sample-count buffer through SampleCountChannel::Edit (whose destructor calls endEdit()) or by calling SampleCountChannel::set(x, y, UINT_MAX) on a valid pixel. This issue has been fixed in versions 3.2.10, 3.3.12, and 3.4.13.
How severe is CVE-2026-55373?
CVE-2026-55373 has a CVSS score of 6.2/10 (MEDIUM severity). The EPSS model estimates a 0.11% probability of exploitation in the next 30 days.
How do I fix CVE-2026-55373?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST