CairoSVG vulnerable to Exponential DoS via recursive <use> element amplification
Priority HIGH 72CWE-674Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-674.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0052 44th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed CairoSVG (Kozea): 2.9.0CairoSVG (PyPI): 2.9.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Kozea | CairoSVG | before 2.9.0 | 2.9.0 | Patch available | CNA |
| — | CairoSVG (PyPI) | before 2.9.0 | 2.9.0 | Patch available | GHSA-f38f-5xpm-9r7c |
- CairoSVG VendorKozea Affected before 2.9.0 Fixed in 2.9.0 Patch available CNA
- CairoSVG (PyPI) Vendor— Affected before 2.9.0 Fixed in 2.9.0 Patch available GHSA-f38f-5xpm-9r7c
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:courtbouillon:cairosvg:*:*:*:*:*:*:*:* | before 2.9.0 | Vulnerable | Courtbouillon |
- cpe:2.3:a:courtbouillon:cairosvg:*:*:*:*:*:*:*:* Versions before 2.9.0 Vulnerable ·Courtbouillon
Remediation
- Fix · CNA CairoSVG (Kozea) Fixed in 2.9.0
- Fix · GHSA-f38f-5xpm-9r7c CairoSVG (PyPI) Fixed in 2.9.0 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-31899
- 2026-10-03 Alias added: GHSA-f38f-5xpm-9r7c
References
More Kozea vulnerabilities
- TI-2026-69644 Inefficient path parsing in CairoSVG enables denial of service CVSS 4.0HIGH 8.7
- TI-2025-42134 WeasyPrint Vulnerable to Server-Side Request Forgery (SSRF) Protection Bypass via HTTP Redirect CVSS 3.1HIGH 7.5
- TI-2026-36607 WeasyPrint: CSS Injection via Presentational Hints CVSS 3.1MEDIUM 6.5
- TI-2026-39778 WeasyPrint restrictive URL fetcher bypass allows local file read and SSRF CVSS 3.1MEDIUM 6.2
- TI-2023-12296 CairoSVG improperly processes SVG files loaded from external resources CVSS 3.1CRITICAL 9.9
- TI-2026-68895 WeasyPrint passes EPS images to Ghostscript, risking code execution CVSS 3.1HIGH 8.8
Sources
- CVE-2026-31899 · CVE Program
- CVE-2026-31899 · NVD
- FIRST EPSS
- GHSA-f38f-5xpm-9r7c · GitHub Advisory Database · CC BY 4.0
- CVE-2026-31899 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences