CVE-2019-20056

Name: CVE-2019-20056
Creator: NVD / NIST
Published: 2019-12-29T19:15:11.167+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.94%

Last modified Jun 17, 2026

CVE-2019-20056 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. stb_image.h (aka the stb image loader) 2.23, as used in libsixel and other products, has an assertion failure in stbi__shiftsigned.. EPSS estimates a 0.94% chance of exploitation in the next 30 days.

Description

stb_image.h (aka the stb image loader) 2.23, as used in libsixel and other products, has an assertion failure in stbi__shiftsigned.

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

0.94%

56.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-617

Affected Software

Vendor	Product	Versions
Nothings	Stb Image.H	2.23

References

https://github.com/saitoha/libsixel/issues/126Exploit, Third Party Advisory
https://github.com/saitoha/libsixel/issues/126Exploit, Third Party Advisory

Timeline

Published: Dec 29, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-20056?

stb_image.h (aka the stb image loader) 2.23, as used in libsixel and other products, has an assertion failure in stbi__shiftsigned.

How severe is CVE-2019-20056?

CVE-2019-20056 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.94% probability of exploitation in the next 30 days.

How do I fix CVE-2019-20056?

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-2019-20056?

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

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Source: NVD / NIST