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.

CVSS v3 7.1 HIGH

7.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.2

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1	Release Notes
https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72c	Exploit Vendor Advisory
https://github.com/saitoha/libsixel/security/advisories/GHSA-c854-ffg9-g72c	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

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

History

No history.

Information

Published : 2026-04-14 22:16

Updated : 2026-07-25 10:10

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

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