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Fencer Intel
medium 6.2

CVE-2026-55373 json

OpenEXR: OpenEXRUtil SampleCountChannel endEdit() can loop forever on UINT_MAX sample counts

published 4mo ago modified 30d ago also EUVD-2026-65185 , GHSA-mff9-68x3-h8rh

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository AcademySoftwareFoundation/openexr. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
6.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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.

Patch / fix

  • openexr openexr 3.2.10, 3.3.12, 3.4.13
  • openexr Debian 13 3.2.12-1~deb13u1
  • openexr Debian 14 3.4.14-0.1

debian advisories DEBIAN-CVE-2026-55373

  • openexr SLE Module for Desktop Applications 15 SP7 2.2.1-150000.3.52.1
  • openexr SLES for SAP applications 16.0, SLES 16.0 3.2.2-160000.9.1

suse advisories SUSE-SU-2026:3169-1SUSE-SU-2026:22653-1

  • openexr openSUSE Leap 16.0 3.2.2-160000.9.1
  • openexr openSUSE Tumbleweed 3.4.13-1.1

opensuse advisories openSUSE-SU-2026:21336-1openSUSE-SU-2026:11218-1

Is CVE-2026-55373 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-55373 updated cvss 6.2

openexr: OpenEXR: Denial of Service via infinite loop in sample count processing.

  • Red Hat Enterprise Linux 8 OpenEXR, OpenEXR-libs Red Hat Enterprise Linux 9 openexr, openexr-libs Red Hat Enterprise Linux 10 openexr
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 OpenEXR, OpenEXR-libs Red Hat Enterprise Linux 7 OpenEXR, OpenEXR-libs
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-mff9-68x3-h8rh referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.2 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Inferred packages

No advisory lists a package for this vulnerability yet. The CVE names these as products and links their GitHub repository, and the package registry names the same repository, so they are probably the affected packages. Low confidence: the versions are the CVE’s own for the product, and a stack check reports the package as unchecked when there are none.

ecosystem package repository affected
pypi openexr academysoftwarefoundation/openexr no versions given

Affected products

  • AcademySoftwareFoundation openexr

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of AcademySoftwareFoundation/openexr published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.