CVE-2021-21236

Name: CVE-2021-21236
Creator: NVD / NIST
Published: 2021-01-06T17:15:23.733+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 1.47%

Last modified Jun 17, 2026

CVE-2021-21236 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. CairoSVG is a Python (pypi) package. CairoSVG is an SVG converter based on Cairo. EPSS estimates a 1.47% chance of exploitation in the next 30 days.

Description

CairoSVG is a Python (pypi) package. CairoSVG is an SVG converter based on Cairo. In CairoSVG before version 2.5.1, there is a regular expression denial of service (REDoS) vulnerability. When processing SVG files, the python package CairoSVG uses two regular expressions which are vulnerable to Regular Expression Denial of Service (REDoS). If an attacker provides a malicious SVG, it can make cairosvg get stuck processing the file for a very long time. This is fixed in version 2.5.1. See Referenced GitHub advisory for more information.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

1.47%

70.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-400

Affected Software

Vendor	Product	Versions
Courtbouillon	Cairosvg	< 2.5.1

References

https://github.com/Kozea/CairoSVG/commit/cfc9175e590531d90384aa88845052de53d94bf3Patch, Third Party Advisory
https://github.com/Kozea/CairoSVG/releases/tag/2.5.1Release Notes, Third Party Advisory
https://github.com/Kozea/CairoSVG/security/advisories/GHSA-hq37-853p-g5cfExploit, Third Party Advisory
https://pypi.org/project/CairoSVG/Product, Third Party Advisory
https://github.com/Kozea/CairoSVG/commit/cfc9175e590531d90384aa88845052de53d94bf3Patch, Third Party Advisory
https://github.com/Kozea/CairoSVG/releases/tag/2.5.1Release Notes, Third Party Advisory
https://github.com/Kozea/CairoSVG/security/advisories/GHSA-hq37-853p-g5cfExploit, Third Party Advisory
https://pypi.org/project/CairoSVG/Product, Third Party Advisory

Timeline

Published: Jan 6, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21236?

How severe is CVE-2021-21236?

CVE-2021-21236 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 1.47% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21236?

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-2021-21236?

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

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Source: NVD / NIST