Heap overwrite via overflowing image stride calculation
Published Mar 31, 2026 · Updated Mar 31, 2026
Integer overflow in Artifex Software MuPDF 1.27.0 and earlier allows attackers to corrupt heap memory by processing a crafted PDF image. pdf_load_image_imp validates attacker-controlled image dimensions against SIZE_MAX even though downstream stride arithmetic uses int; fz_unpack_stream then allocates from the wrapped stride and writes past the heap buffer. Exploitation requires an affected application to render the PDF, typically causing a crash, while successful memory-corruption exploitation runs code in that application's context.
Summary
What happened
Integer overflow in Artifex Software MuPDF 1.27.0 and earlier allows attackers to corrupt heap memory by processing a crafted PDF image. pdf_load_image_imp validates attacker-controlled image dimensions against SIZE_MAX even though downstream stride arithmetic uses int; fz_unpack_stream then allocates from the wrapped stride and writes past the heap buffer. Exploitation requires an affected application to render the PDF, typically causing a crash, while successful memory-corruption exploitation runs code in that application's context.
The record
- CVE
- CVE-2026-3308
- Published
- Mar 31, 2026
- Updated
- Mar 31, 2026
- Vendor
- Artifex Software, Inc.
- Product
- MuPDF
- Classifications
- CWE-190, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 31, 2026CVE publishedPublication date reported by the CVE source.
- Mar 31, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=1.27.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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