WeasyPrint: CSS Injection via Presentational Hints

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-49452
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-18 18:17:49 UTC
Updated2026-08-19 16:17:15 UTC
DescriptionWeasyPrint 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS: 0.002730000 probability, percentile 0.197850000 (date 2026-08-19)

Problem Types: CWE-74 | CWE-74 CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Kozea WeasyPrint affected < 69.0 Not specified

References

ReferenceSourceLinkTags
github.com/Kozea/WeasyPrint/security/advisories/GHSA-jhhc-3hcp-qhm5 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/Kozea/WeasyPrint/releases/tag/v69.0 [email protected] github.com
github.com/Kozea/WeasyPrint/commit/e158264e33fa399b29f415d30719c1d85a55df1d [email protected] github.com
github.com/Kozea/WeasyPrint/pull/2773 [email protected] github.com
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