FKIE_CVE-2026-109449

Vulnerability from fkie_nvd - Published: 2026-10-15 16:17 - Updated: 2026-10-16 16:00
Severity
8.7 (High) - 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
Summary
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.
References
596c5446-0ce5-4ba2-aa66-48b3b757a647https://github.com/symfony/symfony/pull/65690
596c5446-0ce5-4ba2-aa66-48b3b757a647https://github.com/symfony/symfony/pull/66720
596c5446-0ce5-4ba2-aa66-48b3b757a647https://github.com/symfony/symfony/pull/66723
596c5446-0ce5-4ba2-aa66-48b3b757a647https://github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr
596c5446-0ce5-4ba2-aa66-48b3b757a647https://symfony.com/blog/cve-2026-109449-unbounded-nesting-in-the-expression-parser-lets-untrusted-expressions-crash-the-process
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://packagist.org/packages/symfony/expression-language",
          "defaultStatus": "unaffected",
          "modules": [
            "ExpressionLanguage::lint()"
          ],
          "packageName": "symfony/expression-language",
          "product": "symfony",
          "repo": "https://github.com/symfony/expression-language",
          "vendor": "sensiolabs",
          "versions": [
            {
              "lessThan": "v5.4.54",
              "status": "affected",
              "version": "0",
              "versionType": "git"
            },
            {
              "lessThan": "v6.4.48",
              "status": "affected",
              "version": "v6.0.0-BETA1",
              "versionType": "git"
            },
            {
              "lessThan": "v7.4.21",
              "status": "affected",
              "version": "v7.0.0-BETA1",
              "versionType": "git"
            },
            {
              "lessThan": "v8.1.9",
              "status": "affected",
              "version": "v8.0.0-BETA1",
              "versionType": "git"
            }
          ]
        }
      ],
      "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647"
    }
  ],
  "cveTags": [],
  "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."
    }
  ],
  "id": "CVE-2026-109449",
  "lastModified": "2026-10-16T16:00:33.533",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.7,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-109449",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-15T18:05:16.968511Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-15T16:17:43.963",
  "references": [
    {
      "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
      "url": "https://github.com/symfony/symfony/pull/65690"
    },
    {
      "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
      "url": "https://github.com/symfony/symfony/pull/66720"
    },
    {
      "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
      "url": "https://github.com/symfony/symfony/pull/66723"
    },
    {
      "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
      "url": "https://github.com/symfony/symfony/security/advisories/GHSA-7rpj-w9pf-39rr"
    },
    {
      "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
      "url": "https://symfony.com/blog/cve-2026-109449-unbounded-nesting-in-the-expression-parser-lets-untrusted-expressions-crash-the-process"
    }
  ],
  "sourceIdentifier": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-674"
        }
      ],
      "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
      "type": "Secondary"
    }
  ]
}



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