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PatchSiren cyber security CVE debrief

CVE-2026-49286 pontedilana CVE debrief

CVE-2026-49286 is a high-severity remote code execution vulnerability in the PhpWeasyPrint library. The issue arises from a case-sensitive blacklist that fails to guard against PHAR stream wrappers, allowing attackers to bypass security checks and execute arbitrary code. This vulnerability affects PhpWeasyPrint versions prior to 2.6.0 and is a patch-bypass of CVE-2023-28115. Defenders should prioritize patching due to the high CVSS score of 8.1.

Vendor
pontedilana
Product
php-weasyprint
CVSS
HIGH 8.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-19
Original CVE updated
2026-06-22
Advisory published
2026-06-19
Advisory updated
2026-06-22

Who should care

Developers and administrators using PhpWeasyPrint, especially those supporting PHP 7.4+, should be aware of this vulnerability. The issue's severity and potential for remote code execution make it a priority for security teams to assess and mitigate.

Technical summary

The vulnerability in PhpWeasyPrint stems from a flawed blacklist that guards output filenames against PHAR stream wrappers. The blacklist is case-sensitive, while PHP stream wrappers are case-insensitive. This discrepancy allows attackers to bypass the blacklist by using different casing (e.g., PHAR:// or Phar://), which can then trigger the deserialization of a crafted PHAR archive's metadata. On PHP 7.4+, this leads to remote code execution. The issue is addressed in PhpWeasyPrint version 2.6.0.

Defensive priority

High priority due to CVSS score of 8.1 and potential for remote code execution

Recommended defensive actions

  • Upgrade PhpWeasyPrint to version 2.6.0 or later
  • Review and inventory systems using PhpWeasyPrint
  • Monitor for suspicious PHAR archive usage
  • Implement compensating controls to limit exposure
  • Review official advisories for additional mitigation strategies

Evidence notes

The CVE record (cve.org) and NVD detail (nvd.nist.gov) provide official information on CVE-2026-49286. The vulnerability is described as a remote code execution issue due to insecure PHAR deserialization in PhpWeasyPrint versions before 2.6.0. The CVSS score is 8.1, indicating high severity. A patch is available in version 2.6.0, and this issue is a patch-bypass of CVE-2023-28115.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-49286 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-49286

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-49286 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-49286

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.