CVE-2026-44638

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

CVSS v3 2.5 LOW

2.5^/10

CVSS v3 : LOW

Vector :

Exploitability : 1.0 / Impact : 1.4

Attack Vector LOCAL

Attack Complexity HIGH

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w	Exploit Vendor Advisory
https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

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

History

15 May 2026, 17:54

Type	Values Removed	Values Added
CPE		cpe:2.3:a:saitoha:libsixel::::::::
First Time		Saitoha Saitoha libsixel
References	~~() https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w -~~	() https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w - Exploit, Vendor Advisory

15 May 2026, 15:16

Type	Values Removed	Values Added
References	~~() https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w -~~	() https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w -

14 May 2026, 20:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-14 20:17

Updated : 2026-05-15 17:54

NVD link : CVE-2026-44638

Mitre link : CVE-2026-44638

CVE.ORG link : CVE-2026-44638

JSON object : View

Products Affected

saitoha

libsixel

CWE

CWE-476

NULL Pointer Dereference

CWE-690

Unchecked Return Value to NULL Pointer Dereference

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