What’s Vulnerable › Vulnerabilities

CVE-2026-49452: WeasyPrint: CSS Injection via Presentational Hints

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-18 · updated 2026-10-22
• Weakness: CWE-74

Description

WeasyPrint helps web developers to create PDF documents. Prior to 69.0, WeasyPrint embeds unescaped HTML presentational-hint attribute values into CSS in weasyprint/css/__init__.py when presentational_hints=True. The background attribute is inserted into a background-image:url() declaration and parsed by tinycss2.parse_blocks_contents(), allowing untrusted HTML to inject additional CSS declarations. Applications that render untrusted HTML with presentational hints enabled can be affected by CSS injection and server-side requests through injected url() values. This issue is fixed in version 69.0.

Affected products

• Kozea WeasyPrint: before 69.0

References

• https://github.com/Kozea/WeasyPrint/commit/e158264e33fa399b29f415d30719c1d85a55df1d
• https://github.com/Kozea/WeasyPrint/pull/2773
• https://github.com/Kozea/WeasyPrint/releases/tag/v69.0
• https://github.com/Kozea/WeasyPrint/security/advisories/GHSA-jhhc-3hcp-qhm5
• https://github.com/Kozea/WeasyPrint/security/advisories/GHSA-jhhc-3hcp-qhm5

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