CVE-2020-21548

Name: CVE-2020-21548
Creator: NVD / NIST
Published: 2021-09-17T21:15:07.36+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.03%

Last modified Jun 17, 2026

CVE-2020-21548 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. Libsixel 1.8.3 contains a heap-based buffer overflow in the sixel_encode_highcolor function in tosixel.c.. EPSS estimates a 1.03% chance of exploitation in the next 30 days.

Description

Libsixel 1.8.3 contains a heap-based buffer overflow in the sixel_encode_highcolor function in tosixel.c.

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

1.03%

59.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Saitoha	Libsixel	1.8.3

References

https://github.com/saitoha/libsixel/issues/116Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/saitoha/libsixel/issues/116Exploit, Issue Tracking, Patch, Third Party Advisory

Timeline

Published: Sep 17, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-21548?

Libsixel 1.8.3 contains a heap-based buffer overflow in the sixel_encode_highcolor function in tosixel.c.

How severe is CVE-2020-21548?

CVE-2020-21548 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.03% probability of exploitation in the next 30 days.

How do I fix CVE-2020-21548?

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-2020-21548?

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

Scan your code now

Source: NVD / NIST