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Fencer Intel
medium 6.5

CVE-2026-26981 json

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

published 8mo ago modified 3mo ago also EUVD-2026-7407 , GHSA-q6vj-wxvf-5m8c , JLSEC-2026-140 , PYSEC-2026-2849

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

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.

Patch / fix

  • pypi openexr 3.3.7, 3.4.5
  • julia OpenEXR_jll 3.4.8+0
  • openexr openexr 3.3.7, 3.4.5
  • openexr openSUSE Tumbleweed 3.4.5-1.1

opensuse advisories openSUSE-SU-2026:10272-1

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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-2026-26981 updated cvss 6.5

openexr: OpenEXR: Denial of Service via heap-buffer-overflow when parsing a malformed EXR file

  • Red Hat Enterprise Linux 6 OpenEXR, OpenEXR-libs Red Hat Enterprise Linux 7 OpenEXR, OpenEXR-libs Red Hat Enterprise Linux 8 OpenEXR, OpenEXR-libs Red Hat Enterprise Linux 9 openexr, openexr-libs Red Hat Enterprise Linux 10 openexr
    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
8mo ago

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-q6vj-wxvf-5m8c referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi openexr
>=3.3.0, <3.3.7
>=3.4.0, <3.4.5
3.3.7
3.4.5
julia OpenEXR_jll
>=3.4.4+0, <3.4.8+0
3.4.8+0

Affected products

  • AcademySoftwareFoundation openexr

Classification

Weakness
  • CWE-195 Signed to Unsigned Conversion Error

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.