CVE-2026-44638
libsixel: NULL pointer dereference
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.
INFO
Published Date :
May 14, 2026, 8:17 p.m.
Last Modified :
May 14, 2026, 9:21 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-44638
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | [email protected] |
Solution
- Update libsixel to version 1.8.7-r2.
- Recompile and redeploy affected applications.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-44638.
| URL | Resource |
|---|---|
| https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-44638 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-44638
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-44638 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-44638 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
May. 14, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L Added CWE CWE-476 Added CWE CWE-690 Added Reference https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w