AcademySoftwareFoundation OpenEXR up to 3.3.6/3.4.4 EXR File Parser ImfContextInit.cpp istream_nonparallel_read signed conversion

Summaryinfo

A vulnerability classified as problematic has been found in AcademySoftwareFoundation OpenEXR up to 3.3.6/3.4.4. This vulnerability affects the function istream_nonparallel_read of the file ImfContextInit.cpp of the component EXR File Parser. Performing a manipulation results in signed conversion. This vulnerability was named CVE-2026-26981. The attack may be initiated remotely. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in AcademySoftwareFoundation OpenEXR up to 3.3.6/3.4.4. This affects the function istream_nonparallel_read of the file ImfContextInit.cpp of the component EXR File Parser. The manipulation with an unknown input leads to a signed conversion vulnerability. CWE is classifying the issue as CWE-195. The product uses a signed primitive and performs a cast to an unsigned primitive, which can produce an unexpected value if the value of the signed primitive can not be represented using an unsigned primitive. This is going to have an impact on availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-26981 since 02/17/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 299904 (Linux Distros Unpatched Vulnerability : CVE-2026-26981), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.3.7 or 3.4.5 eliminates this vulnerability. Applying the patch 6bb2ddf1068573d073edf81270a015b38cc05cef is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (299904). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• AcademySoftwareFoundation

Name

• OpenEXR

Version

• 3.3.0
• 3.3.1
• 3.3.2
• 3.3.3
• 3.3.4
• 3.3.5
• 3.3.6
• 3.4.0
• 3.4.1
• 3.4.2
• 3.4.3
• 3.4.4

License

• open-source

Website

• Product: https://github.com/AcademySoftwareFoundation/openexr/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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