CVE-2026-55373
MEDIUMDescription
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 to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 1% of all known CVEs.
References
Related Vulnerabilities
Other CWE-190 (Integer Overflow) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-16040 | Medium | 6.5 | 100% | - | Fix |
| CVE-2019-11477 | High | 7.5 | 99% | - | Fix |
| CVE-2023-44443 | High | 7.8 | 94% | - | Fix |
| CVE-2014-0569 | High | 9.3 | 92% | - | - |
| CVE-2017-3599 | High | 7.5 | 84% | - | Fix |
| CVE-2023-21716 | Critical | 9.8 | 82% | - | Fix |
Common questions
How do I fix CVE-2026-55373?
Upgrade openexr on debian unstable to 3.4.14-0.1 or later.
Is CVE-2026-55373 being actively exploited?
Not that we know of. CVE-2026-55373 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.11% is the estimated probability that it will be exploited in the next 30 days. That is higher than 1% of all scored CVEs.
How severe is CVE-2026-55373?
CVE-2026-55373 has a CVSS v3 base score of 6.2, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-55373 affect?
Published advisories record a fix for openexr (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-25.