CVE-2026-44638

LOW

2.5

CVSS v3

Description

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.

CWE-476NULL Pointer Dereference CWE-690

How to fix

Remediation Available

libsixelDebian

Fixed in:1:1.8.7-r2-1CVE-2026-44638

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityHigh

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L

Exploit Intelligence

0.13%probability of exploitation in 30 days

3rdpercentile

Low risk: more likely to be exploited than 3% of all known CVEs.

References

Exploit1

github.com

Related Vulnerabilities

Other CWE-476 (NULL Pointer Dereference) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-21758	High	7.5	93%	-	Fix
CVE-2023-21547	High	7.5	89%	-	Fix
CVE-2014-3470	Medium	4.3	86%	-	Fix
CVE-2021-44224	High	8.2	82%	-	Fix
CVE-2016-0742	High	7.5	82%	-	Fix
CVE-2009-1386	Medium	5.0	80%	-	Fix

Common questions

How do I fix CVE-2026-44638?

Upgrade libsixel on debian unstable to 1:1.8.7-r2-1 or later.

Is CVE-2026-44638 being actively exploited?

Not that we know of. CVE-2026-44638 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.13% is the estimated probability that it will be exploited in the next 30 days. That is higher than 3% of all scored CVEs.

How severe is CVE-2026-44638?

CVE-2026-44638 has a CVSS v3 base score of 2.5, rated low. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-44638 affect?

Published advisories record a fix for libsixel (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2026-44638

Markdown

[![CVE-2026-44638](https://tridentstack.com/cve/badge/CVE-2026-44638.svg)](https://tridentstack.com/cve/CVE-2026-44638)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-44638"><img src="https://tridentstack.com/cve/badge/CVE-2026-44638.svg" alt="CVE-2026-44638"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

See how it works Start freeThis CVE lookup is free and always will be.

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-15.