GHSA-JHHC-3HCP-QHM5中危已审查

WeasyPrint has CSS Injection via Presentational Hints

OSV 1.4.0 · github-reviewed · 修改于 2026-07-07 01:29

发布时间

2026-07-07 01:29

GitHub 审查时间

2026-07-07 01:29

NVD 发布时间

—

源文件

advisories/github-reviewed/2026/07/GHSA-jhhc-3hcp-qhm5/GHSA-jhhc-3hcp-qhm5.json

公告说明

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

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

受影响的软件包

标识信息

别名 / CVE

CVE-2026-49452

CWE

CWE-74

软件生态

PyPI

扩展资料

暂无扩展资料。

CVSS 评分

CVSS_V3

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

原始 OSV JSON

{
  "id": "GHSA-jhhc-3hcp-qhm5",
  "aliases": [
    "CVE-2026-49452"
  ],
  "details": "### Summary\nA 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.\n\n### Details\nFile: weasyprint/css/__init__.py\n\nThe `background` attribute is used to construct CSS:\n\nbackground-image:url({element.get(\"background\")})\n\nThis string is parsed by `tinycss2.parse_blocks_contents()`.\n\nBecause the value is not escaped, additional CSS declarations can be injected.\n\n### PoC\n<body background=\"x);background-image:url(http://169.254.169.254/latest/meta-data/)\">\n\n### Impact\n- CSS injection\n- Server-side requests via injected `url()`\n- Limited to cases where `presentational_hints=True`\n\n### Suggested Fix\n- Escape attribute values before embedding into CSS\n- Restrict allowed values for presentational hints\n[VULN-05_css_injection_presentational_hints.md](https://github.com/user-attachments/files/26370718/VULN-05_css_injection_presentational_hints.md)",
  "summary": "WeasyPrint has CSS Injection via Presentational Hints",
  "affected": [
    {
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "68.1"
            }
          ]
        }
      ],
      "package": {
        "name": "weasyprint",
        "ecosystem": "PyPI"
      }
    }
  ],
  "modified": "2026-07-06T17:29:53Z",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"
    }
  ],
  "published": "2026-07-06T17:29:53Z",
  "references": [
    {
      "url": "https://github.com/Kozea/WeasyPrint/security/advisories/GHSA-jhhc-3hcp-qhm5",
      "type": "WEB"
    },
    {
      "url": "https://github.com/Kozea/WeasyPrint",
      "type": "PACKAGE"
    }
  ],
  "schema_version": "1.4.0",
  "database_specific": {
    "cwe_ids": [
      "CWE-74"
    ],
    "severity": "MODERATE",
    "github_reviewed": true,
    "nvd_published_at": null,
    "github_reviewed_at": "2026-07-06T17:29:53Z"
  }
}