libsixel before 1.8.7-r1 and 1.9.0 through 1.10.5 contains a heap out-of-bounds write vulnerability in gif_init_frame() in src/fromgif.c, which never checks the GIF transparent color index against the palette size. Attackers can supply a crafted GIF with a small color table and large transparent index, processed with a background color set, to write bytes past the palette buffer, causing heap corruption or crashes.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 2
- StatusReceived → DeferredNVD modified 2026-10-16 19:18
- First seenCVSS 5.8NVD modified 2026-10-14 15:17
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 8
- https://github.com/libsixel/libsixel/blob/v1.10.5/src/fromgif.c#L219-L240
- https://github.com/saitoha/libsixel/blob/v1.8.7/src/fromgif.c#L182-L248
- https://github.com/saitoha/libsixel/commit/bdbab09816eb9188429c37a50b97c5e66dfe5047
- https://github.com/saitoha/libsixel/issues/220
- https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1
- https://hackmd.io/@haind-pwn/libsixel-gif-transparent-index-oob-write
- https://www.vulncheck.com/advisories/libsixel-before-1.8.7-r1-and-1.9.0-through-1.10.5-heap-out-of-bounds-write-via-gif
- https://github.com/saitoha/libsixel/issues/220