Process crash or memory disclosure via unsigned underflow
Published Apr 12, 2026 · Updated Apr 12, 2026
Integer underflow in libexif 0 through 0.6.25 allows attackers to crash applications or disclose process memory via crafted EXIF MakerNotes. The Fuji and Olympus value getters subtract one from an unsigned entry count before checking the requested index, so a zero count wraps and lets an invalid index pass. Exploitation requires a libexif-using program to decode attacker-controlled MakerNote data; the bounded outcomes are a process crash or disclosure of adjacent memory, not data modification.
Summary
What happened
Integer underflow in libexif 0 through 0.6.25 allows attackers to crash applications or disclose process memory via crafted EXIF MakerNotes. The Fuji and Olympus value getters subtract one from an unsigned entry count before checking the requested index, so a zero count wraps and lets an invalid index pass. Exploitation requires a libexif-using program to decode attacker-controlled MakerNote data; the bounded outcomes are a process crash or disclosure of adjacent memory, not data modification.
The record
- CVE
- CVE-2026-40386
- Published
- Apr 12, 2026
- Updated
- Apr 12, 2026
- Vendor
- libexif Project
- Product
- libexif
- Classifications
- CWE-191
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 12, 2026CVE publishedPublication date reported by the CVE source.
- Apr 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <=0.6.25
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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