Bug 2442135 (CVE-2026-26981)

Summary: CVE-2026-26981 openexr: OpenEXR: Denial of Service via heap-buffer-overflow when parsing a malformed EXR file
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: gtanzill, jbuscemi
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in OpenEXR. A remote attacker could exploit a heap-buffer-overflow vulnerability in the `istream_nonparallel_read` function by tricking a user into opening a specially crafted EXR file. This occurs when a signed integer subtraction results in a negative value that is then converted to a large unsigned size, leading to an out-of-bounds read during a memory copy operation. Successful exploitation of this vulnerability could lead to a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2442257    
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Description OSIDB Bzimport 2026-02-24 03:01:42 UTC 
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.