Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A heap buffer overflow write vulnerability exists in GIMP's Paint Shop Pro (PSP) file format parser. In read_channel_data() in file-psp.c, for low bit-depth images (depth=1 or 4), line_width uses a packed formula (8 pixels/byte) but fread() reads width bytes (1 byte/pixel). For example, with width=33 and depth=1: allocates 4 bytes, writes 33 — a 29-byte heap overflow.

This is a variant of CVE-2026-4153 (commit 98cb1371), which fixed read_layer_block() but left the buf allocation in read_channel_data() unpatched.

- Function: read_channel_data()
- File: plug-ins/common/file-psp.c:1558-1784
- Fix: https://gitlab.gnome.org/GNOME/gimp/-/commit/b630f167
- Hardening: https://gitlab.gnome.org/GNOME/gimp/-/commit/20b00d6d
- Upstream issue: https://gitlab.gnome.org/GNOME/gimp/-/issues/16205
- Acknowledgment: bb1abu