XXE in Sensiolabs Symfony
CVE-2026-45133
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, when the parser is exposed to attacker-controlled input, deeply nested mappings or sequences cause both the block-level (Parser::parseBlock()) and inline (Inline::parseSequence() / Inline::parseMapping()) parsers to recurse without a depth limit. A crafted document exhausts the PHP stack and crashes the worker. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
EPSS: 0.006 (47.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Sensiolabs Symfony
- Symfony — versions < 5.4.52, >= 6.0.0-BETA1, < 6.4.40, >= 7.0.0-BETA1, < 7.4.12
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-45133?
- CVE-2026-45133 is a high-severity vulnerability in Sensiolabs Symfony, classified under Uncontrolled Recursion. CVSS score: 7.5/10. Published 2026-07-14.
- How severe is CVE-2026-45133?
- High severity. CVSS v3 base score is 7.5 out of 10.