The PNG chunk reader has no notion of chunk ordering. It records whether an IDAT has been seen and whether a tRNS has already supplied transparency, but nothing prevents an IHDR being read a second time.
A PNG carries exactly one IHDR and it is the first chunk. A file that places a second one after IDAT rewrites the image width, height, bit depth and pixel depth *after* the decoded-data buffer has already been allocated and filled from the original values. The pass that reverses the PNG row filters then derives its own extent from the new dimensions and walks the old allocation, moving image bytes past the end of it.
The buffer is allocated by GUIX rather than supplied by the caller, so the application has no way to size it defensively. The decoder is compiled in by default.
CVSS
No CVSS.
References
Configurations
No configuration.
History
20 Oct 2026, 15:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-10-20 15:17
Updated : 2026-10-20 19:48
NVD link : CVE-2026-91186
Mitre link : CVE-2026-91186
CVE.ORG link : CVE-2026-91186
JSON object : View
Products Affected
No product.