CVE-2026-34378
Received Received - Intake
Signed Integer Overflow in OpenEXR dataWindow Causes Crash

Publication date: 2026-04-06

Last updated on: 2026-04-07

Assigner: GitHub, Inc.

Description
OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.4.0 to before 3.4.9, a missing bounds check on the dataWindow attribute in EXR file headers allows an attacker to trigger a signed integer overflow in generic_unpack(). By setting dataWindow.min.x to a large negative value, OpenEXRCore computes an enormous image width, which is later used in a signed integer multiplication that overflows, causing the process to terminate with SIGILL via UBSan. This vulnerability is fixed in 3.4.9.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2026-04-06
Last Modified
2026-04-07
Generated
2026-06-16
AI Q&A
2026-04-06
EPSS Evaluated
2026-06-15
NVD
CVE-2026-34378
EUVD
EUVD-2026-19303
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
openexr openexr From 3.4.0 (inc) to 3.4.9 (exc)
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
Attack-Flow Graph
AI Quick Actions
Instant insights powered by AI
Compliance Impact

The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

Executive Summary

This vulnerability exists in OpenEXR versions from 3.4.0 to before 3.4.9. It involves a missing bounds check on the dataWindow attribute in EXR file headers. An attacker can exploit this by setting dataWindow.min.x to a large negative value, which causes a signed integer overflow in the generic_unpack() function. Specifically, OpenEXRCore calculates an enormous image width from this value, leading to a signed integer multiplication overflow. This overflow causes the process to terminate unexpectedly with a SIGILL signal triggered by Undefined Behavior Sanitizer (UBSan). The issue is fixed in version 3.4.9.

Impact Analysis

The primary impact of this vulnerability is a denial of service condition. By exploiting the signed integer overflow, an attacker can cause the affected process to crash with a SIGILL signal. This can disrupt applications or services that use OpenEXR to process EXR image files, potentially leading to service interruptions or instability.

Mitigation Strategies

To mitigate this vulnerability, upgrade OpenEXR to version 3.4.9 or later, where the signed integer overflow issue in generic_unpack() has been fixed.

Detection Guidance

This vulnerability involves a signed integer overflow triggered by crafted EXR files with a negative dataWindow.min.x value. Detection involves identifying or analyzing EXR files that may exploit this condition.

To detect this vulnerability on your system, you can:

  • Check the version of OpenEXR installed to ensure it is 3.4.9 or later, as versions before 3.4.9 are vulnerable.
  • Scan for suspicious or crafted EXR files that contain a negative dataWindow.min.x value in their headers.

Suggested commands:

  • Use a package manager or command to check the installed OpenEXR version, for example: `openexr --version` or `dpkg -l | grep openexr` on Debian-based systems.
  • Use a hex editor or a custom script to inspect EXR file headers for the dataWindow.min.x attribute and check if it contains large negative values.
  • Monitor application logs for crashes or SIGILL signals related to OpenEXR processing, which may indicate exploitation attempts.
Chat Assistant
Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-34378. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70
EPSS Chart