CVE-2026-45133CWE-1333CWE-674CWE-776

Symfony: [Yaml] Harden the parser when handling untrusted input

High · published July 14, 2026

CVSS v4.0
8.2
EPSS
1%
Percentile
49.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.2 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
EPSS
0.00630 · 49.5th percentile
Weaknesses
CWE-1333 · Inefficient Regular Expression Complexity; CWE-674 · Uncontrolled Recursion; CWE-776 · Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
Published
2026-07-14T18:45Z
EPSS history
Timeline
  • 14 JUL 18:45Z
    Symfony: [Yaml] Harden the parser when handling untrusted input
    cvelistv5