Buffer overflow in Saitoha Libsixel
CVE-2026-110601
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.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/saitoha/libsixel/issues/220 (issue-tracking)
- github.com/saitoha/libsixel/commit/bdbab09816eb9188429c37a50b97c5e66dfe5047 (patch)
- github.com/saitoha/libsixel/releases/tag/v1.8.7-r1 (release-notes)
- github.com/saitoha/libsixel/blob/v1.8.7/src/fromgif.c (technical-description)
- github.com/libsixel/libsixel/blob/v1.10.5/src/fromgif.c (technical-description)
- hackmd.io/@haind-pwn/libsixel-gif-transparent-index-oob-write (third-party-advisory)
- www.vulncheck.com/advisories/libsixel-before-1.8.7-r1-and-1.9.0-through-1.10.5-… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-110601?
- CVE-2026-110601 is a medium-severity vulnerability in Saitoha Libsixel, classified under Out-of-bounds Write. CVSS score: 6.3/10. Published 2026-10-14.
- How severe is CVE-2026-110601?
- Medium severity. CVSS v3 base score is 6.3 out of 10.