{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-109449", "assignerOrgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647", "state": "PUBLISHED", "assignerShortName": "Checkmarx", "dateReserved": "2026-10-12T16:57:32.590Z", "datePublished": "2026-10-15T15:19:08.663Z", "dateUpdated": "2026-10-15T15:30:42.730Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647", "shortName": "Checkmarx", "dateUpdated": "2026-10-15T15:30:42.730Z"}, "title": "Symfony: Unbounded Nesting in the Expression Parser Lets Untrusted Expressions Crash the Process", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-674", "description": "CWE-674 Uncontrolled Recursion", "type": "CWE"}]}], "affected": [{"vendor": "sensiolabs", "product": "symfony", "collectionURL": "https://packagist.org/packages/symfony/expression-language", "packageName": "symfony/expression-language", "repo": "https://github.com/symfony/expression-language", "modules": ["ExpressionLanguage::lint()"], "versions": [{"status": "affected", "version": "0", "lessThan": "v5.4.54", "versionType": "git"}, {"status": "affected", "version": "v6.0.0-BETA1", "lessThan": "v6.4.48", "versionType": "git"}, {"status": "affected", "version": "v7.0.0-BETA1", "lessThan": "v7.4.21", "versionType": "git"}, {"status": "affected", "version": "v8.0.0-BETA1", "lessThan": "v8.1.9", "versionType": "git"}], "defaultStatus": "unaffected"}], "cpeApplicability": [{"operator": "OR", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*", "versionStartIncluding": "0", "versionEndExcluding": "v5.4.54"}, {"vulnerable": true, "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*", "versionStartIncluding": "v6.0.0-beta1", "versionEndExcluding": "v6.4.48"}, {"vulnerable": true, "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*", "versionStartIncluding": "v7.0.0-beta1", "versionEndExcluding": "v7.4.21"}, {"vulnerable": true, "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*", "versionStartIncluding": "v8.0.0-beta1", "versionEndExcluding": "v8.1.9"}]}]}], "descriptions": [{"lang": "en", "value": "In\u00a0Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9,\u00a0the 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.\n\n\n#[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.\n\nThis issue affects symfony/expression-language\u00a0through v5.4.53, v6.0.0-BETA1\u00a0through\u00a0v6.4.47, v7.0.0-BETA1\u00a0through\u00a0v7.4.20, and v8.0.0-BETA1\u00a0through\u00a0v8.1.8.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "In&nbsp;<span>Symfony Expression Language versions prior to 5.4.54, 6.4.48, 7.4.21, and 8.1.9,&nbsp;</span><span>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.</span><div><code><br></code></div><div><code>#[Assert\\ExpressionSyntax]</code><span> passes the validated value to </span><code>ExpressionLanguage::lint()</code><span>, so an application validating expressions written by its users could be crashed by a single request, and so could any code parsing untrusted expressions.</span></div><div><span>This issue affects </span><code>symfony/expression-language</code><span>&nbsp;through v5.4.53, v6.0.0-BETA1&nbsp;</span>through<span>&nbsp;v6.4.47, v7.0.0-BETA1&nbsp;</span>through<span>&nbsp;v7.4.20, and v8.0.0-BETA1&nbsp;</span>through<span>&nbsp;v8.1.8.</span></div>"}]}], "references": [{"url": "https://github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr", "tags": ["third-party-advisory"]}, {"url": "https://symfony.com/blog/cve-2026-109449-unbounded-nesting-in-the-expression-parser-lets-untrusted-expressions-crash-the-process", "tags": ["vendor-advisory"]}, {"url": "https://github.com/symfony/symfony/pull/65690", "tags": ["patch"]}, {"url": "https://github.com/symfony/symfony/pull/66720", "tags": ["patch"]}, {"url": "https://github.com/symfony/symfony/pull/66723", "tags": ["patch"]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "HIGH", "baseScore": 8.7, "vectorString": "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"}}], "credits": [{"lang": "en", "value": "Nicolas Grekas", "type": "remediation developer"}], "source": {"discovery": "UNKNOWN"}, "x_generator": {"engine": "Vulnogram 1.0.5"}}}}

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