What is CVE-2020-11721?

CVE-2020-11721 is a medium-severity vulnerability in Saitoha Libsixel, classified under Access of Uninitialized Pointer. CVSS score: 6.5/10. Published 2020-04-12.

How severe is CVE-2020-11721?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Saitoha Libsixel

CVE-2020-11721

load_png in loader.c in libsixel.a in libsixel 1.8.6 has an uninitialized pointer leading to an invalid call to free, which can cause a denial of service.

Published 2020-04-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.009 (59.5th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 59.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Saitoha Libsixel — versions 1.8.6

Weakness classification (CWE)

CWE-824 — Access of Uninitialized Pointer

References

github.com/saitoha/libsixel/issues/134 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2020-11721?: CVE-2020-11721 is a medium-severity vulnerability in Saitoha Libsixel, classified under Access of Uninitialized Pointer. CVSS score: 6.5/10. Published 2020-04-12.
How severe is CVE-2020-11721?: Medium severity. CVSS v3 base score is 6.5 out of 10.