weasyprint Has Server-Side Request Forgery (SSRF)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-55073: 0.22% estimated exploitation activity in the next 30 days; percentile 13.26 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary urlfetcher is WeasyPrint's documented mechanism for restricting resource loading - applications use it to block file://, internal hosts, etc. when rendering untrusted input. Two writepdf() channels ignore the document's urlfetcher and build a fresh default URLFetcher() instead. A restrictive fetcher set on HTML() is silently bypassed for: - xmpmetadata=[url] - the URL is fetched and the bytes are embedded verbatim in the output PDF. This is an arbitrary local file read when the path is attacker-influenced. - stylesheets=[urlorpath] - the sheet is fetched and applied. This is SSRF / arbitrary local-or-internal resource loading, and it is transitive: the permissive fetcher propagates through the whole @import / url() graph. Applications affected are those that (1) run WeasyPrint server-side, (2) set a restrictive urlfetcher to block file:// or internal hosts, and (3) forward an attacker-influenced URL/path into either parameter - e.g. PDF rendering APIs, invoice/report…

Published by the source

9 Sep 2026, 18:06 UTC

Last modified by the source

10 Sep 2026, 12:26 UTC

Source last checked

26 Oct 2026, 13:51 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-jf6q-chmf-3h3v

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-jf6q-chmf-3h3v

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-jf6q-chmf-3h3v

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# Patch Next advisory brief: CVE-2026-55073

Advisory: weasyprint Has Server-Side Request Forgery (SSRF)
IDs: CVE-2026-55073, GHSA-jf6q-chmf-3h3v
Record: https://patchnext.com/advisories/cve-2026-55073 (revision 3, source checked 26 Oct 2026, 13:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: weasyprint 70.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI weasyprint: affected < 70.0; fixed in 70.0

## Suggested inspection (read-only)
- `python -m pip show weasyprint`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on weasyprint.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jf6q-chmf-3h3v (GitHub-reviewed advisory GHSA-jf6q-chmf-3h3v lists affected ranges: PyPI weasyprint >=0 <70.0)
- Verified: https://osv.dev/vulnerability/GHSA-jf6q-chmf-3h3v (OSV record GHSA-jf6q-chmf-3h3v lists affected ranges: PyPI weasyprint >=0 <70.0 (fixed))

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