Inefficient regular expression complexity in Symfony - CVE-2026-45756
Published: May 21, 2026
Vulnerability identifier: #VU132055
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-45756
CWE-ID: CWE-1333
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 cause a denial of service.
The vulnerability exists due to inefficient regular expression complexity in the JsonPath match() and search() filter functions when evaluating an attacker-influenced JSONPath expression against non-trivial JSON input. A remote attacker can supply a specially crafted JSONPath expression containing a catastrophic-backtracking pattern to cause a denial of service.
The issue occurs when server-side code passes attacker-controlled JSONPath input to JsonCrawler for evaluation.
How to mitigate CVE-2026-45756
Install security update from vendor's website.