libexif up to 0.6.25 MakerNote Decoding integer underflow

Summaryinfo

A vulnerability, which was classified as critical, has been found in libexif up to 0.6.25. Impacted is an unknown function of the component MakerNote Decoding. This manipulation causes integer underflow. This vulnerability appears as CVE-2026-40386. The attack may be initiated remotely. There is no available exploit. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability has been found in libexif up to 0.6.25 and classified as critical. Affected by this vulnerability is an unknown functionality of the component MakerNote Decoding. The manipulation with an unknown input leads to a integer underflow vulnerability. The CWE definition for the vulnerability is CWE-191. The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In libexif through 0.6.25, an integer underflow in size checking for Fuji and Olympus MakerNote decoding could be used by attackers to crash or leak information out of libexif-using programs.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-40386 since 04/12/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 306059 (Linux Distros Unpatched Vulnerability : CVE-2026-40386), which helps to determine the existence of the flaw in a target environment.

Applying the patch dc6eac6e9655d14d0779d99e82d0f5f442d2f34b is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at Tenable (306059). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• libexif

Version

• 0.6.0
• 0.6.1
• 0.6.2
• 0.6.3
• 0.6.4
• 0.6.5
• 0.6.6
• 0.6.7
• 0.6.8
• 0.6.9
• 0.6.10
• 0.6.11
• 0.6.12
• 0.6.13
• 0.6.14
• 0.6.15
• 0.6.16
• 0.6.17
• 0.6.18
• 0.6.19
• 0.6.20
• 0.6.21
• 0.6.22
• 0.6.23
• 0.6.24
• 0.6.25

License

• open-source

Website

• Product: https://github.com/libexif/libexif/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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