TI-2026-39952 Aliases CVE-2026-55373

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

MEDIUM 61CWE-190Published 2026-08-25 · Updated 2026-08-25

Key facts

Attack vector: Local
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-190 and the CVSS impact.

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00157 4th percentileScored 2026-11-07

Fix Partial openexr (AcademySoftwareFoundation): 3.2.10, 3.3.12, 3.4.13Red Hat: 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
AcademySoftwareFoundation	openexr	before 3.2.10; 3.3.0 to before 3.3.12; 3.4.0 to before 3.4.13	3.2.10, 3.3.12, 3.4.13	Patch available	CNA

openexr VendorAcademySoftwareFoundation Affected before 3.2.10; 3.3.0 to before 3.3.12; 3.4.0 to before 3.4.13 Fixed in 3.2.10, 3.3.12, 3.4.13 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:openexr:openexr::::::::	—	—	Academy Software Foundation

cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:* Versions — — ·Academy Software Foundation

Remediation

Fix · CNA openexr (AcademySoftwareFoundation) Fixed in 3.2.10, 3.3.12, 3.4.13

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 8	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred

Not affected: 2 products

Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7

Timeline

2026-10-02 Threatist record created from CVE-2026-55373

References

Other 1

https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-mff9-68x3-h8rh

TI-2026-30739 OpenColorIO vulnerable to stack buffer overflow via unbounded `sscanf %s` in Spi3D (.spi3d) LUT parser CVSS 4.0HIGH 8.4
TI-2026-38605 OpenEXR: Unhandled assert abort in HTJ2K decoder via crafted QCD marker (DoS) CVSS 4.0HIGH 7.1
TI-2026-48281 OpenEXR: Heap out-of-bounds write in exrmultiview with subsampled channel union CVSS 3.1HIGH 7.1
TI-2026-48279 OpenEXR: Heap buffer overflow in PyOpenEXR from literal/prefixed RGB channel name collision CVSS 3.1HIGH 7.1
TI-2026-42768 OpenEXR: Heap OOB read in SampleCountChannel row when using nonzero dataWindow CVSS 3.1HIGH 7.1
TI-2026-42338 OpenEXR: Out-of-bounds read in DeepImageChannel::row() for non-zero dataWindow origin CVSS 3.1HIGH 7.1

See all 26 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences