CVE-2026-42216 in OpenEXR
Summary
by MITRE • 05/07/2026
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From versions 3.0.0 to before 3.2.9, 3.3.0 to before 3.3.11, and 3.4.0 to before 3.4.11, IDManifest::init() reconstructs strings from a prefix-compressed representation. If the previous string is longer than 255 bytes, the next string is expected to begin with a 2-byte prefix length. The code reads stringList[i][0] and stringList[i][1] without checking that the current string has at least two bytes. This issue has been patched in versions 3.2.9, 3.3.11, and 3.4.11.
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Analysis
by VulDB Data Team • 07/02/2026
The OpenEXR library represents a critical component in the motion picture industry for image storage and processing, with the EXR file format serving as a standard for high dynamic range imaging. This vulnerability affects multiple version ranges including 3.0.0 through 3.2.8, 3.3.0 through 3.3.10, and 3.4.0 through 3.4.10, highlighting a fundamental flaw in the IDManifest::init() function that handles string reconstruction from prefix-compressed representations. The vulnerability stems from improper bounds checking during string processing where the code assumes sufficient string length without validation. When processing strings that exceed 255 bytes in length, the system expects subsequent strings to begin with a 2-byte prefix length indicator, yet the implementation fails to verify that the current string contains at least two bytes before attempting to read stringList[i][0] and stringList[i][1]. This represents a classic buffer over-read condition that falls under CWE-129, specifically involving insufficient validation of length parameters. The operational impact of this vulnerability extends beyond simple memory corruption as it could enable remote code execution or denial of service attacks when processing malformed EXR files, particularly in environments where untrusted input is processed. Attackers could exploit this by crafting specially constructed EXR files that trigger the vulnerable code path, potentially leading to arbitrary code execution on systems processing these files. The vulnerability aligns with ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain unauthorized access or execute malicious code. Organizations using OpenEXR libraries in production environments must urgently patch to versions 3.2.9, 3.3.11, and 3.4.11 to mitigate this risk. The fix implemented addresses the core issue by adding proper bounds checking before accessing the string data, ensuring that stringList[i][0] and stringList[i][1] are only accessed when the string length is sufficient. This remediation follows security best practices for input validation and buffer management, aligning with industry standards for secure coding practices. The vulnerability demonstrates the importance of proper bounds checking in string manipulation operations, particularly when handling compressed or encoded data structures where metadata validation is critical for system stability and security.