CVE-2026-26981
Description
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.
Statement
The vulnerable code was introduced in OpenEXR 3.3.0 via commit https://github.com/AcademySoftwareFoundation/openexr/commit/c3e212e9c76c4d174f5624564f9103dc49ca1fd8.
OpenEXR 1.x (shipped in RHEL 6 and RHEL 7) and OpenEXR 2.x (shipped in RHEL 8) do not include the affected context implementation and are therefore not impacted. RHEL 9, RHEL 10 and RHIVOS-2 ship OpenEXR 3.1.x versions, which predate the introduction of the vulnerable code path and are also not affected.
Aditionally, Starting with OpenEXR 3.x, IlmBase was split out into a separate project named Imath. Imath provides math and numerical types, while OpenEXR contains all EXR file parsing logic.
This vulnerability exists within OpenEXR’s file parsing logic and does not affect the separate IlmBase or Imath libraries, which contain only mathematical and utility components and no file decoding functionality
Mitigation
No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | Required | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Instability
This weakness will generally lead to undefined behavior and therefore crashes. In the case of overflows involving loop index variables, the likelihood of infinite loops is also high.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the wrap around results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.
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