CVE-2021-40656

Name: CVE-2021-40656
Creator: NVD / NIST
Published: 2022-04-08T16:15:08.117+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.00%

Last modified Jun 17, 2026

CVE-2021-40656 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. libsixel before 1.10 is vulnerable to Buffer Overflow in libsixel/src/quant.c:867.. EPSS estimates a 1.00% chance of exploitation in the next 30 days.

Description

libsixel before 1.10 is vulnerable to Buffer Overflow in libsixel/src/quant.c:867.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

1.00%

58.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Libsixel	Libsixel	< 1.10.0

References

https://github.com/libsixel/libsixel/issues/25Exploit, Issue Tracking, Third Party Advisory
https://github.com/libsixel/libsixel/issues/25Exploit, Issue Tracking, Third Party Advisory

Timeline

Published: Apr 8, 2022
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-40656?

libsixel before 1.10 is vulnerable to Buffer Overflow in libsixel/src/quant.c:867.

How severe is CVE-2021-40656?

CVE-2021-40656 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.00% probability of exploitation in the next 30 days.

How do I fix CVE-2021-40656?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-40656?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST