CVE-2026-110601 Details
Description
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.
A heap out-of-bounds write vulnerability has been identified in libsixel versions prior to 1.8.7-r1 and in the 1.9.0 through 1.10.5 range. The issue arises in the GIF loader component, specifically within the 'gif_init_frame' function of 'src/fromgif.c'. The vulnerability occurs because the GIF transparent color index is not validated against the palette size. Attackers can exploit this by crafting a GIF with a small color table and a large transparent index, which, when processed with a background color set, leads to writing bytes beyond the palette buffer. This exploitation causes heap corruption or crashes.
Users can update to libsixel version 1.8.7-r1 or version 1.9.0 and later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 14, 2026CISA-ADP
Assessed Oct 20, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/saitoha/libsixel/issues/220 | CISA-ADP | ExploitIssue TrackingTechnical DescriptionVendor |
| https://github.com/libsixel/libsixel/blob/v1.10.5/src/fromgif.c#L219-L240 | [email protected] | Source CodeVendor |
| https://github.com/saitoha/libsixel/blob/v1.8.7/src/fromgif.c#L182-L248 | [email protected] | Source CodeVendor |
| https://github.com/saitoha/libsixel/commit/bdbab09816eb9188429c37a50b97c5e66dfe5047 | [email protected] | Source CodeVendor |
| https://github.com/saitoha/libsixel/issues/220 | [email protected] | ExploitIssue TrackingTechnical DescriptionVendor |
| https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1 | [email protected] | Release NotesVendor |
| https://hackmd.io/@haind-pwn/libsixel-gif-transparent-index-oob-write | [email protected] | ExploitTechnical Analysis |
| 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 | [email protected] | AdvisoryBundleRemedy |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-787 | Out-of-bounds Write | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| libsixel | < 1.8.7-r1 (semver) >= 1.9.0, <= 1.10.5 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 20, 2026 | CVE Modified | CISA-ADP |
| Oct 14, 2026 | New CVE Received | [email protected] |