XML External Entity injection in Symfony - CVE-2026-45071
Published: May 21, 2026
Vulnerability identifier: #VU132065
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-45071
CWE-ID: CWE-611
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: SensioLabs
Affected software:
Symfony
Symfony
Detailed vulnerability description
The vulnerability allows a remote attacker to disclose local files.
The vulnerability exists due to improper restriction of xml external entity references in DomCrawler::addXmlContent() when parsing attacker-supplied XML content with validateOnParse enabled. A remote attacker can supply a specially crafted XML document containing a file:// external entity to disclose local files.
The issue occurs because DTD subset processing and external entity resolution are re-enabled, and LIBXML_NONET does not block file:// entity resolution.
How to mitigate CVE-2026-45071
Install security update from vendor's website.