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Vulnerability · Published Aug 18, 2026 · Assigned by GitHub_M

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

Medium 6.5

In plain English

A medium-severity injection in WeasyPrint from Kozea. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.4%top 68.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12weasyprintno fix listedDEBIAN-CVE-2026-49452
Debian:13weasyprintno fix listedDEBIAN-CVE-2026-49452
Debian:14weasyprint69.0-1DEBIAN-CVE-2026-49452
PyPIweasyprintno fix listedGHSA-jhhc-3hcp-qhm5
PyPIweasyprintno fix listedPYSEC-2026-3412
Ubuntu:22.04:LTSweasyprintno fix listedUBUNTU-CVE-2026-49452
Ubuntu:24.04:LTSweasyprintno fix listedUBUNTU-CVE-2026-49452
Ubuntu:25.10weasyprintno fix listedUBUNTU-CVE-2026-49452
Ubuntu:26.04:LTSweasyprintno fix listedUBUNTU-CVE-2026-49452
Ubuntu:26.10weasyprintno fix listedUBUNTU-CVE-2026-49452

Affected products (as reported)

VendorProductVersions
Kozea WeasyPrint < 69.0

Weakness: CWE-74 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

References