Raw vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-34545 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Openexr Openexr. Its CVSS base score is 8.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 46th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34545 is a heap-based buffer overflow vulnerability (CWE-122) combined with an integer overflow (CWE-190) in the OpenEXR library, which provides the specification and reference implementation for the EXR image file format used in the motion picture industry. The issue affects versions 3.4.0 through 3.4.6 and occurs when decoding a specially crafted .exr file that uses HTJ2K compression with a channel width of 32768 pixels. This triggers controlled writes beyond the output heap buffer, with a primitive of 2 bytes per overflow iteration (or 4 bytes via an alternate path), repeating for each additional pixel past the overflow point. Any application that processes or decodes EXR images using the vulnerable OpenEXR library is at risk.
An attacker with local access (AV:L) and low privileges (PR:L) can exploit this vulnerability by convincing a user (UI:R) to open the malicious .exr file in a vulnerable application. Successful exploitation enables controlled heap writes, which can lead to remote code execution on impacted systems, with high impacts on confidentiality, integrity, and availability (CVSS 7.3). The scoped impact remains unchanged (S:U), making it suitable for privilege escalation or arbitrary code execution in local contexts such as image viewers, editors, or rendering software.
The vulnerability has been addressed in OpenEXR version 3.4.7, as detailed in the project's security advisory (GHSA-ghfj-fx47-wg97), release notes, and the patching commit (3827998f5c041d6a94c6af24bbb363daa669e4b3). Security practitioners should update to 3.4.7 or later and audit dependencies in applications handling EXR files for the vulnerable range.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-18062
Vulnerability Data
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From version 3.4.0 to before version 3.4.7, an attacker providing a crafted .exr file with HTJ2K compression and a…
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channel width of 32768 can write controlled data beyond the output heap buffer in any application that decodes EXR images. The write primitive is 2 bytes per overflow iteration or 4 bytes (by another path), repeating for each additional pixel past the overflow point. In this context, a heap write overflow can lead to remote code execution on systems. This issue has been patched in version 3.4.7.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V6.7.2V1.4.1V1.4.2V2.1.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (including fuzzing and memory-error detectors) can discover heap overflows after they have been coded.
Input validation enforces bounds checking on data written to heap buffers, directly stopping the overflow condition from being introduced.
Security engineering principles require use of memory-safe constructs and bounds-checked allocation routines that avoid introducing heap overflows.
Memory-protection mechanisms limit the ability of a heap overflow to execute attacker-controlled code or corrupt adjacent structures.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.
Vulnerability scanning and recording can discover heap-overflow flaws but does not prevent their introduction in code.
Timely patching removes known heap-overflow instances after they exist.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development and acceptance can detect heap overflows before release.
Secure development lifecycle mandates practices that reduce the likelihood of introducing heap overflows.
Application security requirements can specify bounds-checking and safe memory APIs that mitigate heap overflows.
Secure architecture and engineering principles include memory-safety and input-validation controls that address heap overflows.
Secure coding standards directly prescribe techniques (safe functions, bounds checks) that prevent heap-based buffer overflows.
Change management ensures controlled deployment of fixes for discovered heap-overflow vulnerabilities.