CVE-2026-40930
LIBPNG: Chunk smuggling in push-mode APNG parser via unconsumed chunk body
- State
- Published
- Severity
- 5.4 Medium
- Published
- Jun 4, 2026
- Updated
- Jun 4, 2026
- Reserved
- Apr 15, 2026
Description
LIBPNG is a reference library for use in applications that process PNG (Portable Network Graphics) raster image files. In version 1.8.0, three inter-frame chunk discard paths in the push-mode APNG parser clear the chunk-header flag without consuming the chunk body and CRC, allowing attacker-controlled bytes inside an ignored ancillary chunk to be reinterpreted as a fresh chunk header on the next call to `png_process_data`. Commit faf06924688b62d7c1654b5ceddedbde66ffadb4 fixes the issue.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.4 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L | GitHub_M |
Weaknesses
- CWE-436 Interpretation Conflict
Affected Products
| Product | Versions |
|---|---|
libpngpnggroup |
|
libpng-apngpnggroup |
|
References
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