CVE-2026-33019

7.1 HIGH
Published: April 14, 2026 Modified: April 23, 2026
View on NVD

Description

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1
Source: security-advisories@github.com
Release Notes
https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72c
Source: security-advisories@github.com
Exploit Vendor Advisory
https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72c
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Vendor Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.1 / 10.0
EPSS (Exploit Probability)
0.0%
0th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

saitoha