CVE-2026-31899 CairoSVG vulnerable to Exponential DoS via recursive <use> element amplification

High 7.5 Published 13 Mar 2026 Updated 16 Mar 2026

An attacker can cause CPU exhaustion and denial of service by submitting a crafted SVG file with recursive use elements to applications using CairoSVG.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-31899?

CVE-2026-31899 is a high-severity denial of service vulnerability in Kozea CairoSVG, published on 13 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

CairoSVG is an SVG converter based on Cairo, a 2D graphics library. Prior to Kozea/CairoSVG has exponential denial of service via recursive <use> element amplification in cairosvg/defs.py. This causes CPU exhaustion from a small input.

Weakness: CWE-674

Which versions are affected by CVE-2026-31899?

3 open source packages ship an affected version, including cairosvg and CairoSVG. It affects 1 product.

Package	Affected	Fixed in
`cairosvg` PyPI	All versions	`2.9.0`
`cairosvg` PyPI	All versions	`2.9.0`
`CairoSVG` PyPI	All versions	`2.9.0`

Linux distribution packages (6)

`python-CairoSVG` SUSE:Linux Enterprise Module for Python 3 15 SP7	All versions	`2.7.1-150400.9.6.1`
`python-CairoSVG` SUSE:Linux Enterprise Server 16.0	All versions	`2.7.1-160000.3.1`
`python-CairoSVG` SUSE:Linux Enterprise Server for SAP applications 16.0	All versions	`2.7.1-160000.3.1`
`python-CairoSVG` openSUSE:Leap 15.6	All versions	`2.7.1-150400.9.6.1`
`ansible-creator` openSUSE:Tumbleweed	All versions	`26.8.0-1.1`
`python-CairoSVG` openSUSE:Tumbleweed	All versions	`2.9.0-1.1`

Products include Courtbouillon Cairosvg.

How do I fix CVE-2026-31899?

Upgrade cairosvg to 2.9.0 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-31899 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31899 exists.

Public exploit code: 1 proofs of concept on GitHub.

Sources

Also known as DEBIAN-CVE-2026-31899, GHSA-f38f-5xpm-9r7c, MGASA-2026-0104, PYSEC-2026-2122, ROOT-APP-PYPI-CVE-2026-31899, SUSE-SU-2026:1421-1 and 5 more.