CVE-2026-33019

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain an integer overflow leading to an out-of-bounds heap read in the --crop option handling of img2sixel, where positive coordinates up to INT_MAX are accepted without overflow-safe bounds checking. In sixel_encoder_do_clip(), the expression clip_w + clip_x overflows to a large negative value when clip_x is INT_MAX, causing the bounds guard to be skipped entirely, and the unclamped coordinate is passed through sixel_frame_clip() to clip(), which computes a source pointer far beyond the image buffer and passes it to memmove(). An attacker supplying a specially crafted crop argument with any valid image can trigger an out-of-bounds read in the heap, resulting in a reliable crash and potential information disclosure. This issue has been fixed in version 1.8.7-r1.
Configurations

Configuration 1 (hide)

cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:*

History

23 Apr 2026, 14:47

Type Values Removed Values Added
First Time Saitoha
Saitoha libsixel
CPE cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:*
References () https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1 - () https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1 - Release Notes
References () https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72c - () https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72c - Exploit, Vendor Advisory

15 Apr 2026, 20:16

Type Values Removed Values Added
References () https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72c - () https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72c -

14 Apr 2026, 22:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-04-14 22:16

Updated : 2026-04-23 14:47


NVD link : CVE-2026-33019

Mitre link : CVE-2026-33019

CVE.ORG link : CVE-2026-33019


JSON object : View

Products Affected

saitoha

  • libsixel
CWE
CWE-125

Out-of-bounds Read

CWE-190

Integer Overflow or Wraparound