CVE-2020-21049

Name: CVE-2020-21049
Creator: NVD / NIST
Published: 2021-09-14T16:15:08.773+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.34%

Last modified Jun 17, 2026

CVE-2020-21049 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.. EPSS estimates a 1.34% chance of exploitation in the next 30 days.

Description

An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

1.34%

67.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-125

Affected Software

Vendor	Product	Versions
Saitoha	Libsixel	< 1.8.5

References

https://bitbucket.org/netbsd/pkgsrc/commits/970a81d31ec7498e04d09b6b7771cef35f63cd28Broken Link
https://github.com/saitoha/libsixel/blob/master/ChangeLogRelease Notes, Third Party Advisory
https://github.com/saitoha/libsixel/commit/0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33dPatch, Release Notes, Third Party Advisory
https://github.com/saitoha/libsixel/issues/74Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/saitoha/libsixel/releases/tag/v1.8.5Release Notes, Third Party Advisory
https://bitbucket.org/netbsd/pkgsrc/commits/970a81d31ec7498e04d09b6b7771cef35f63cd28Broken Link
https://github.com/saitoha/libsixel/blob/master/ChangeLogRelease Notes, Third Party Advisory
https://github.com/saitoha/libsixel/commit/0b1e0b3f7b44233f84e5c9f512f8c90d6bbbe33dPatch, Release Notes, Third Party Advisory
https://github.com/saitoha/libsixel/issues/74Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/saitoha/libsixel/releases/tag/v1.8.5Release Notes, Third Party Advisory

Timeline

Published: Sep 14, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2020-21049?

An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.

How severe is CVE-2020-21049?

CVE-2020-21049 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.34% probability of exploitation in the next 30 days.

How do I fix CVE-2020-21049?

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-2020-21049?

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

Scan your code now

Source: NVD / NIST