CVE-2026-109413 (GCVE-0-2026-109413)

Vulnerability from cvelistv5 – Published: 2026-10-15 14:57 – Updated: 2026-10-15 18:06
VLAI
Title
Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process
Summary
In Symfony YAML prior to versions 5.4.54, 6.4.45, 7.4.18, and 8.1.6, Yaml\Parser::lexInlineStructure() recursed through lexInlineMapping() and lexInlineSequence() for every { and [ of an inline collection, without entering the nesting level that the rest of the parser bounds with maxNestingLevel. A document made of deeply nested inline collections, such as [[[[...]]]], exhausted the stack while it was being lexed: depending on the PHP version and its stack settings, the process crashed or the request ended with a fatal error. Any code parsing untrusted YAML is affected. That includes #[MapRequestPayload] when the Yaml component is installed and the endpoint does not restrict acceptFormat: a single unauthenticated request with a YAML content type is enough. This issue affects symfony/yaml through v5.4.53, v6.0.0-BETA1 through v6.4.44, v7.0.0-BETA1 through v7.4.17, and v8.0.0-BETA1 through v8.1.5.
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
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-15 18:06 UTC
CWE
Assigner
Checkmarx CNA under the mitre root
CNA scorecard – unranked: 5 records in the last 180 days, 10 needed details
References
Impacted products
Vendor Product Version CPE status
sensiolabs symfony Affected: 0 , < v5.4.54 (git)
Affected: v6.0.0-BETA1 , < v6.4.45 (git)
Affected: v7.0.0-BETA1 , < v7.4.18 (git)
Affected: v8.0.0-BETA1 , < v8.1.6 (git)
    cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
    cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
    cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
    cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
Create a notification for this product.
Credits
Nicolas Grekas
Show details on NVD website
To clipboard 

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                  "value": "\u003cp\u003eIn Symfony YAML prior to versions\u0026nbsp;\u003cspan\u003e5.4.54,\u0026nbsp;\u003c/span\u003e\u003cspan\u003e6.4.45,\u0026nbsp;\u003c/span\u003e\u003cspan\u003e7.4.18, and\u0026nbsp;\u003c/span\u003e\u003cspan\u003e8.1.6,\u0026nbsp;\u003c/span\u003e\u003ccode\u003eYaml\\Parser::lexInlineStructure()\u003c/code\u003e\u003cspan\u003e recursed through \u003c/span\u003e\u003ccode\u003elexInlineMapping()\u003c/code\u003e\u003cspan\u003e and \u003c/span\u003e\u003ccode\u003elexInlineSequence()\u003c/code\u003e\u003cspan\u003e for every \u003c/span\u003e\u003ccode\u003e{\u003c/code\u003e\u003cspan\u003e and \u003c/span\u003e\u003ccode\u003e[\u003c/code\u003e\u003cspan\u003e of an inline collection, without entering the nesting level that the rest of the parser bounds with \u003c/span\u003e\u003ccode\u003emaxNestingLevel\u003c/code\u003e\u003cspan\u003e. A document made of deeply nested inline collections, such as \u003c/span\u003e\u003ccode\u003e[[[[...]]]]\u003c/code\u003e\u003cspan\u003e, exhausted the stack while it was being lexed: depending on the PHP version and its stack settings, the process crashed or the request ended with a fatal error.\u003c/span\u003e\u003c/p\u003e\u003cp\u003eAny code parsing untrusted YAML is affected. That includes \u003ccode\u003e#[MapRequestPayload]\u003c/code\u003e when the Yaml component is installed and the endpoint does not restrict \u003ccode\u003eacceptFormat\u003c/code\u003e: a single unauthenticated request with a YAML content type is enough.\u003c/p\u003e\u003cp\u003eThis issue affects \u003ccode\u003esymfony/yaml\u003c/code\u003e\u0026nbsp;through v5.4.53, v6.0.0-BETA1 through\u0026nbsp;v6.4.44, v7.0.0-BETA1 through\u0026nbsp;v7.4.17, and v8.0.0-BETA1 through\u0026nbsp;v8.1.5.\u003c/p\u003e"
                }
              ],
              "value": "In Symfony YAML prior to versions\u00a05.4.54,\u00a06.4.45,\u00a07.4.18, and\u00a08.1.6,\u00a0Yaml\\Parser::lexInlineStructure() recursed through lexInlineMapping() and lexInlineSequence() for every { and [ of an inline collection, without entering the nesting level that the rest of the parser bounds with maxNestingLevel. A document made of deeply nested inline collections, such as [[[[...]]]], exhausted the stack while it was being lexed: depending on the PHP version and its stack settings, the process crashed or the request ended with a fatal error.\n\n\n\nAny code parsing untrusted YAML is affected. That includes #[MapRequestPayload] when the Yaml component is installed and the endpoint does not restrict acceptFormat: a single unauthenticated request with a YAML content type is enough.\n\n\n\nThis issue affects symfony/yaml\u00a0through v5.4.53, v6.0.0-BETA1 through\u00a0v6.4.44, v7.0.0-BETA1 through\u00a0v7.4.17, and v8.0.0-BETA1 through\u00a0v8.1.5."
            }
          ],
          "metrics": [
            {
              "cvssV4_0": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "baseScore": 8.7,
                "baseSeverity": "HIGH",
                "exploitMaturity": "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",
                "version": "4.0",
                "vulnAvailabilityImpact": "HIGH",
                "vulnConfidentialityImpact": "NONE",
                "vulnIntegrityImpact": "NONE",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-674",
                  "description": "CWE-674 Uncontrolled Recursion",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-10-15T15:29:00.531Z",
            "orgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
            "shortName": "Checkmarx"
          },
          "references": [
            {
              "tags": [
                "third-party-advisory"
              ],
              "url": "https://github.com/symfony/symfony/security/advisories/GHSA-2v3c-qxhr-7vpv"
            },
            {
              "tags": [
                "vendor-advisory"
              ],
              "url": "https://symfony.com/blog/cve-2026-109413-unbounded-recursion-in-the-yaml-inline-lexer-lets-a-single-document-crash-the-process"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/symfony/symfony/pull/65688"
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "Symfony: Unbounded Recursion in the YAML Inline Lexer Lets a Single Document Crash the Process",
          "x_generator": {
            "engine": "Vulnogram 1.0.5"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
        "assignerShortName": "Checkmarx",
        "cveId": "CVE-2026-109413",
        "datePublished": "2026-10-15T14:57:00.211Z",
        "dateReserved": "2026-10-12T15:28:55.069Z",
        "dateUpdated": "2026-10-15T18:06:55.183Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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