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TI-2026-21460 Aliases CVE-2026-26981GHSA-q6vj-wxvf-5m8c

OpenEXR has heap-buffer-overflow via signed integer underflow in ImfContextInit.cpp

Priority MEDIUM 62CWE-195Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. In versions 3.3.0 through 3.3.6 and 3.4.0 through 3.4.4, a heap-buffer-overflow (OOB read) occurs in the `istream_nonparallel_read` function in `ImfContextInit.cpp` when parsing a malformed EXR file through a memory-mapped `IStream`. A signed integer subtraction produces a negative value that is implicitly converted to `size_t`, resulting in a massive length being passed to `memcpy`. Versions 3.3.7 and 3.4.5 contain a patch.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00597 48th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed openexr (AcademySoftwareFoundation): 3.3.7, 3.4.5OpenEXR (PyPI): 3.3.7, 3.4.5

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

VendorProductAffected versionsFixed inStatusSource
AcademySoftwareFoundationopenexr3.3.0 to before 3.3.7; 3.4.0 to before 3.4.53.3.7, 3.4.5Patch availableCNA
—OpenEXR (PyPI)3.3.0 to before 3.3.73.3.7Patch availableGHSA-q6vj-wxvf-5m8c
—OpenEXR (PyPI)3.4.0 to before 3.4.53.4.5Patch availableGHSA-q6vj-wxvf-5m8c
  • openexr VendorAcademySoftwareFoundation Affected 3.3.0 to before 3.3.7; 3.4.0 to before 3.4.5 Fixed in 3.3.7, 3.4.5 Patch available CNA
  • OpenEXR (PyPI) Vendor— Affected 3.3.0 to before 3.3.7 Fixed in 3.3.7 Patch available GHSA-q6vj-wxvf-5m8c
  • OpenEXR (PyPI) Vendor— Affected 3.4.0 to before 3.4.5 Fixed in 3.4.5 Patch available GHSA-q6vj-wxvf-5m8c

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:*3.3.0 to before 3.3.7; 3.4.0 to before 3.4.5VulnerableAcademy Software Foundation
  • cpe:2.3:a:openexr:openexr:*:*:*:*:*:*:*:* Versions 3.3.0 to before 3.3.7; 3.4.0 to before 3.4.5 Vulnerable ·Academy Software Foundation

Remediation

  • Fix · CNA openexr (AcademySoftwareFoundation) Fixed in 3.3.7, 3.4.5
  • Fix · GHSA-q6vj-wxvf-5m8c OpenEXR (PyPI) Fixed in 3.3.7 Advisory →
  • Fix · GHSA-q6vj-wxvf-5m8c OpenEXR (PyPI) Fixed in 3.4.5 Advisory →

Vendor assessments

Red Hat

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

Not affected: 5 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-26981
  2. 2026-10-03 Alias added: GHSA-q6vj-wxvf-5m8c

References

Exploit 1

Patch 2

Advisory 1

Other 1

  • 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