CVE-2026-109449

Description

In Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9, the parser of the ExpressionLanguage component built its node tree with no bound on its depth. An expression made of tens of thousands of nested unary operators, array literals, binary operators or property accesses crashed the PHP process, while the tree was being freed. #[Assert\ExpressionSyntax] passes the validated value to ExpressionLanguage::lint(), so an application validating expressions written by its users could be crashed by a single request, and so could any code parsing untrusted expressions. This issue affects symfony/expression-language through v5.4.53, v6.0.0-BETA1 through v6.4.47, v7.0.0-BETA1 through v7.4.20, and v8.0.0-BETA1 through v8.1.8.

Is your site exposed to CVE-2026-109449?

Run a free security scan — no signup, results in seconds.

Weakness Type (CWE)

CWE-674 CWE-674

References

Other References

https://github.com/symfony/symfony/pull/65690 https://github.com/symfony/symfony/pull/66720 https://github.com/symfony/symfony/pull/66723 https://github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr https://symfony.com/blog/cve-2026-109449-unbounded-nesting-in-the-expression-parser-lets-untrusted-expressions-crash-the-process

Frequently Asked Questions

What is CVE-2026-109449? +

In Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9, the parser of the ExpressionLanguage component built its node tree with no bound on its depth. An expression made of tens of thousands of nested unary operators, array literals, binary operators or property accesses crashed the PHP process, while the tree was being freed. #[Assert\ExpressionSyntax] passes the validated value to ExpressionLanguage::lint(), so an application validating expressions written by its users could be crashed by a single request, and so could any code parsing untrusted expressions. This issue affects symfony/expression-language through v5.4.53, v6.0.0-BETA1 through v6.4.47, v7.0.0-BETA1 through v7.4.20, and v8.0.0-BETA1 through v8.1.8.

How do I check if I'm vulnerable to CVE-2026-109449? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-8936

Fixed a VM panic caused by unbounded recursion in the grpcfuse kernel module when a container created deeply nested directories …

CVE-2025-10728

When the module renders a Svg file that contains a <pattern> element, it might end up rendering it recursively leading …

CVE-2025-11896

In Xpdf 4.05 (and earlier), a PDF object loop in a CMap, via the "UseCMap" entry, leads to infinite recursion …

CVE-2026-46689

Kanidm is an identity management platform. Prior to version 1.9.3, a single unauthenticated GET to any /scim/v1/... endpoint with a …

CVE-2026-44844

eml_parser serves as a python module for parsing eml files and returning various information found in the e-mail as well …

CVE-2026-89418

google-protobuf contains an unbounded recursion when parsing unknown protobuf group fields. An attacker can send a small crafted payload of …