Staging Environment: Content and features may be unstable or change without notice.

Advisory Package Curation

CVE-2026-49452

Progress 0 / 0

Advisory Summaries

github_osv/GHSA-jhhc-3hcp-qhm5

WeasyPrint has CSS Injection via Presentational Hints ### Summary A CSS injection issue exists in WeasyPrint when HTML presentational hints are enabled. Unescaped attribute values are embedded into CSS, allowing injection of arbitrary CSS declarations. This affects applications processing untrusted HTML input. ### Details File: weasyprint/css/__init__.py The `background` attribute is used to construct CSS: background-image:url({element.get("background")}) This string is parsed by `tinycss2.parse_blocks_contents()`. Because the value is not escaped, additional CSS declarations can be injected. ### PoC <body background="x);background-image:url(http://169.254.169.254/latest/meta-data/)"> ### Impact - CSS injection - Server-side requests via injected `url()` - Limited to cases where `presentational_hints=True` ### Suggested Fix - Escape attribute values before embedding into CSS - Restrict allowed values for presentational hints VULN-05_css_injection_presentational_hints.md https://github.com/user-attachments/files/26370718/VULN-05_css_injection_presentational_hints.md

gitlab/pypi/weasyprint/CVE-2026-49452

WeasyPrint has CSS Injection via Presentational Hints A CSS injection issue exists in WeasyPrint when HTML presentational hints are enabled. Unescaped attribute values are embedded into CSS, allowing injection of arbitrary CSS declarations. This affects applications processing untrusted HTML input.

pypa/weasyprint/PYSEC-2026-3412

WeasyPrint has CSS Injection via Presentational Hints ### Summary A CSS injection issue exists in WeasyPrint when HTML presentational hints are enabled. Unescaped attribute values are embedded into CSS, allowing injection of arbitrary CSS declarations. This affects applications processing untrusted HTML input. ### Details File: weasyprint/css/__init__.py The `background` attribute is used to construct CSS: background-image:url({element.get("background")}) This string is parsed by `tinycss2.parse_blocks_contents()`. Because the value is not escaped, additional CSS declarations can be injected. ### PoC <body background="x);background-image:url(http://169.254.169.254/latest/meta-data/)"> ### Impact - CSS injection - Server-side requests via injected `url()` - Limited to cases where `presentational_hints=True` ### Suggested Fix - Escape attribute values before embedding into CSS - Restrict allowed values for presentational hints VULN-05_css_injection_presentational_hints.md https://github.com/user-attachments/files/26370718/VULN-05_css_injection_presentational_hints.md

pysec/PYSEC-2026-3412

WeasyPrint has CSS Injection via Presentational Hints ### Summary A CSS injection issue exists in WeasyPrint when HTML presentational hints are enabled. Unescaped attribute values are embedded into CSS, allowing injection of arbitrary CSS declarations. This affects applications processing untrusted HTML input. ### Details File: weasyprint/css/__init__.py The `background` attribute is used to construct CSS: background-image:url({element.get("background")}) This string is parsed by `tinycss2.parse_blocks_contents()`. Because the value is not escaped, additional CSS declarations can be injected. ### PoC <body background="x);background-image:url(http://169.254.169.254/latest/meta-data/)"> ### Impact - CSS injection - Server-side requests via injected `url()` - Limited to cases where `presentational_hints=True` ### Suggested Fix - Escape attribute values before embedding into CSS - Restrict allowed values for presentational hints VULN-05_css_injection_presentational_hints.md https://github.com/user-attachments/files/26370718/VULN-05_css_injection_presentational_hints.md