PhpWeasyPrint vulnerable to PHAR deserialization via output filename (CVE-2023-28115 case-insensitive bypass)

Exploitation

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

CVSS

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

EPSS

• CVE-2026-49286: 0.73% estimated exploitation activity in the next 30 days; percentile 54.47 (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 pontedilana/php-weasyprint guarded the output filename against the phar:// stream wrapper with a case-sensitive blacklist: PHP stream wrappers are case-insensitive, so PHAR://, Phar://, etc. bypass the check and reach fileExists() (fileexists()) in prepareOutput(). On PHP 7 (which the library still supports — PHP 7.4+), this triggers deserialization of a crafted PHAR archive's metadata, leading to remote code execution. This is the patch-bypass of CVE-2023-28115. The same issue and fix were handled upstream in KnpLabs/snappy (GHSA-92rv-4j2h-8mjj). Affected versions pontedilana/php-weasyprint versions <= 2.5.1 (the case-sensitive guard was introduced in commit eb8accc, "Implement countermeasures for CVE-2023-28115"). Patched in: 2.6.0. Privilege required A caller able to control the output filename passed to generate() / generateFromHtml(), plus the ability to place a PHAR archive on the filesystem (e.g. via an upload). Exploitation of the deserialization requires the server…

Published by the source

26 Jun 2026, 22:10 UTC

Last modified by the source

26 Jun 2026, 22:10 UTC

Source last checked

26 Oct 2026, 14:49 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2fmj-p74r-3wjm

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# Patch Next advisory brief: CVE-2026-49286

Advisory: PhpWeasyPrint vulnerable to PHAR deserialization via output filename (CVE-2023-28115 case-insensitive bypass)
IDs: CVE-2026-49286, GHSA-2fmj-p74r-3wjm
Record: https://patchnext.com/advisories/cve-2026-49286 (revision 1, source checked 26 Oct 2026, 14:49 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pontedilana/php-weasyprint 2.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist pontedilana/php-weasyprint: affected <= 2.5.1; fixed in 2.6.0

## Suggested inspection (read-only)
- Packagist pontedilana/php-weasyprint: check the installed version with your package manager.

## 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 pontedilana/php-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-2fmj-p74r-3wjm (GitHub-reviewed advisory GHSA-2fmj-p74r-3wjm lists affected ranges: Packagist pontedilana/php-weasyprint >=0 <=2.5.1)

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