What is CVE-2026-33018?

CVE-2026-33018 is a high-severity vulnerability in Saitoha Libsixel, classified under Use After Free. CVSS score: 7.0/10. Published 2026-04-14.

How severe is CVE-2026-33018?

High severity. CVSS v3 base score is 7.0 out of 10.

Use After Free in Saitoha Libsixel

CVE-2026-33018

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain a Use-After-Free vulnerability via the load_gif() function in fromgif.c, where a single sixel_frame_t object is reused across a…

Vulnerability class: Use-After-Free

EPSS: 0.000 (6.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.

Affected products

Saitoha Libsixel — versions < 1.8.7-rc1

Weakness classification (CWE)

CWE-416 — Use After Free

References

https://github.com/saitoha/libsixel/security/advisories/GHSA-w46f-jr9f-rgvp (x_refsource_CONFIRM)
https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-33018?: CVE-2026-33018 is a high-severity vulnerability in Saitoha Libsixel, classified under Use After Free. CVSS score: 7.0/10. Published 2026-04-14.
How severe is CVE-2026-33018?: High severity. CVSS v3 base score is 7.0 out of 10.