Vulnerability Database

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Total vulnerabilities in the database

CVE-2026-45756 — symfony / json-path

Description

The JsonPath component's match() and search() filter functions compile a caller-supplied pattern straight into preg_match():

'match' => @preg_match(\sprintf('/^%s$/u', $this->transformJsonPathRegex($argList[1])), $value), 'search' => @preg_match("/{$this->transformJsonPathRegex($argList[1])}/u", $value),

transformJsonPathRegex() only performs cosmetic escaping: there is no length cap, no restriction to the RFC 9485 i-regexp subset, and no bound on backtracking. An application that evaluates an attacker-influenced JSONPath expression server-side (e.g. one taken from a query parameter or API field and passed to JsonCrawler) can therefore be made to run a catastrophic-backtracking pattern such as $[?search(@, "(a+)+$")]. Evaluated against a moderately sized document, this pins a CPU core for seconds per request, so a handful of concurrent requests exhausts the worker pool: a denial of service. Because the preg_match() calls are prefixed with @, the PCRE backtrack-limit errors that would otherwise surface are suppressed, leaving no log trace.

Conditions for exploitation

An application that evaluates an attacker-influenced JSONPath expression containing a match() / search() filter against any non-trivial JSON input.

Resolution

JsonCrawler runs the preg_match() calls through a helper that lowers pcre.backtrack_limit to 10000 for the duration of the call (restoring the previous value afterwards), so a pathological pattern fails fast instead of stalling the worker.

The patch for this issue is available here for branch 7.4.

Credits

Symfony would like to thank Himanshu Anand for reporting the issue and Alexandre Daubois for providing the fix.

No technical information available.

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

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Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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