Heap over-read via truncated row-stride pointer arithmetic
Published Jan 12, 2026 · Updated Jan 12, 2026
Out-of-bounds read in PNG Development Group libpng 1.6.26 through 1.6.53 allows local users to over-read heap memory via row strides. The png_write_image_16bit and png_write_image_8bit paths cast signed ptrdiff_t row_bytes to 16-bit unsigned values before pointer arithmetic, reversing or truncating the offset. Exploitation requires 16-bit linear input and a negative stride or one above 65,535 bytes; the bad offset exposes adjacent heap data or leaves the write loop without forward progress.
Summary
What happened
Out-of-bounds read in PNG Development Group libpng 1.6.26 through 1.6.53 allows local users to over-read heap memory via row strides. The png_write_image_16bit and png_write_image_8bit paths cast signed ptrdiff_t row_bytes to 16-bit unsigned values before pointer arithmetic, reversing or truncating the offset. Exploitation requires 16-bit linear input and a negative stride or one above 65,535 bytes; the bad offset exposes adjacent heap data or leaves the write loop without forward progress.
The record
- CVE
- CVE-2026-22801
- Published
- Jan 12, 2026
- Updated
- Jan 12, 2026
- Vendor
- PNG Development Group
- Product
- libpng
- Classifications
- CWE-190, CWE-125, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 12, 2026CVE publishedPublication date reported by the CVE source.
- Jan 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.6.54
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
- Upstream negative-stride test programproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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