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Vulnerability record · CVE-2021-21236 · published 6 January 2021

CVE-2021-21236: Courtbouillon cairosvg uncontrolled resource consumption vulnerability

Courtbouillon · Cairosvg

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.

5.5 CVSS 3.1 Medium EPSS 1.5% · top 27.4% CWE-400 · Uncontrolled resource consumption
5.5CVSS 3.1 base score, v2 4.3
1.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/Kozea/CairoSVG/commit/cfc9175e590531d90384aa88845052de53d94bf3 PatchThird Party Advisory
https://github.com/Kozea/CairoSVG/releases/tag/2.5.1 Release NotesThird Party Advisory
https://github.com/Kozea/CairoSVG/security/advisories/GHSA-hq37-853p-g5cf ExploitThird Party Advisory
https://pypi.org/project/CairoSVG/ ProductThird Party Advisory
https://github.com/Kozea/CairoSVG/commit/cfc9175e590531d90384aa88845052de53d94bf3 PatchThird Party Advisory
https://github.com/Kozea/CairoSVG/releases/tag/2.5.1 Release NotesThird Party Advisory
https://github.com/Kozea/CairoSVG/security/advisories/GHSA-hq37-853p-g5cf ExploitThird Party Advisory
https://pypi.org/project/CairoSVG/ ProductThird Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-21236), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.