CVE-2026-45304 (GCVE-0-2026-45304)

Vulnerability from cvelistv5 – Published: 2026-07-14 18:48 – Updated: 2026-07-14 19:13
VLAI
Title
Symfony: YAML Parser Exponential Memory Allocation via Recursive Collection-Alias Expansion ("Billion Laughs")
Summary
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.
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 (v2.0.3)
CWE
  • CWE-776 - Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
Assigner
References
Impacted products
Vendor Product Version
symfony symfony Affected: < 5.4.52
Affected: >= 6.0.0-BETA1, < 6.4.40
Affected: >= 7.0.0-BETA1, < 7.4.12
Affected: >= 8.0.0-BETA1, < 8.0.12
Create a notification for this product.
symfony yaml Affected: < 5.4.52
Affected: >= 6.0.0-BETA1, < 6.4.40
Affected: >= 7.0.0-BETA1, < 7.4.12
Affected: >= 8.0.0-BETA1, < 8.0.12
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-45304",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-14T19:13:27.727393Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-14T19:13:39.323Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "symfony",
          "vendor": "symfony",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.4.52"
            },
            {
              "status": "affected",
              "version": "\u003e= 6.0.0-BETA1, \u003c 6.4.40"
            },
            {
              "status": "affected",
              "version": "\u003e= 7.0.0-BETA1, \u003c 7.4.12"
            },
            {
              "status": "affected",
              "version": "\u003e= 8.0.0-BETA1, \u003c 8.0.12"
            }
          ]
        },
        {
          "product": "yaml",
          "vendor": "symfony",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.4.52"
            },
            {
              "status": "affected",
              "version": "\u003e= 6.0.0-BETA1, \u003c 6.4.40"
            },
            {
              "status": "affected",
              "version": "\u003e= 7.0.0-BETA1, \u003c 7.4.12"
            },
            {
              "status": "affected",
              "version": "\u003e= 8.0.0-BETA1, \u003c 8.0.12"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\\Component\\Yaml\\Parser resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "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"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-776",
              "description": "CWE-776: Improper Restriction of Recursive Entity References in DTDs (\u0027XML Entity Expansion\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-14T18:48:49.329Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4"
        },
        {
          "name": "https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a"
        },
        {
          "name": "https://github.com/symfony/symfony/releases/tag/v5.4.52",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/symfony/symfony/releases/tag/v5.4.52"
        },
        {
          "name": "https://github.com/symfony/symfony/releases/tag/v6.4.40",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/symfony/symfony/releases/tag/v6.4.40"
        },
        {
          "name": "https://github.com/symfony/symfony/releases/tag/v7.4.12",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/symfony/symfony/releases/tag/v7.4.12"
        },
        {
          "name": "https://github.com/symfony/symfony/releases/tag/v8.0.12",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/symfony/symfony/releases/tag/v8.0.12"
        }
      ],
      "source": {
        "advisory": "GHSA-4qpc-3hr4-r2p4",
        "discovery": "UNKNOWN"
      },
      "title": "Symfony: YAML Parser Exponential Memory Allocation via Recursive Collection-Alias Expansion (\"Billion Laughs\")"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-45304",
    "datePublished": "2026-07-14T18:48:49.329Z",
    "dateReserved": "2026-05-11T20:14:43.202Z",
    "dateUpdated": "2026-07-14T19:13:39.323Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-45304",
      "date": "2026-07-15",
      "epss": "0.00761",
      "percentile": "0.51119"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-45304\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-07-14T19:17:07.050\",\"lastModified\":\"2026-07-14T20:25:54.190\",\"vulnStatus\":\"Undergoing Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\\\\Component\\\\Yaml\\\\Parser resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"symfony\",\"product\":\"symfony\",\"versions\":[{\"version\":\"\u003c 5.4.52\",\"status\":\"affected\"},{\"version\":\"\u003e= 6.0.0-BETA1, \u003c 6.4.40\",\"status\":\"affected\"},{\"version\":\"\u003e= 7.0.0-BETA1, \u003c 7.4.12\",\"status\":\"affected\"},{\"version\":\"\u003e= 8.0.0-BETA1, \u003c 8.0.12\",\"status\":\"affected\"}]},{\"vendor\":\"symfony\",\"product\":\"yaml\",\"versions\":[{\"version\":\"\u003c 5.4.52\",\"status\":\"affected\"},{\"version\":\"\u003e= 6.0.0-BETA1, \u003c 6.4.40\",\"status\":\"affected\"},{\"version\":\"\u003e= 7.0.0-BETA1, \u003c 7.4.12\",\"status\":\"affected\"},{\"version\":\"\u003e= 8.0.0-BETA1, \u003c 8.0.12\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"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\",\"baseScore\":8.7,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"HIGH\",\"subConfidentialityImpact\":\"NONE\",\"subIntegrityImpact\":\"NONE\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"NOT_DEFINED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-07-14T19:13:27.727393Z\",\"id\":\"CVE-2026-45304\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-776\"}]}],\"references\":[{\"url\":\"https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/symfony/symfony/releases/tag/v5.4.52\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/symfony/symfony/releases/tag/v6.4.40\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/symfony/symfony/releases/tag/v7.4.12\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/symfony/symfony/releases/tag/v8.0.12\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4\",\"source\":\"security-advisories@github.com\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-45304\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-14T19:13:27.727393Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-14T19:13:34.393Z\"}}], \"cna\": {\"title\": \"Symfony: YAML Parser Exponential Memory Allocation via Recursive Collection-Alias Expansion (\\\"Billion Laughs\\\")\", \"source\": {\"advisory\": \"GHSA-4qpc-3hr4-r2p4\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV4_0\": {\"version\": \"4.0\", \"baseScore\": 8.7, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"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\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"attackRequirements\": \"NONE\", \"privilegesRequired\": \"NONE\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"NONE\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"HIGH\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"NONE\"}}], \"affected\": [{\"vendor\": \"symfony\", \"product\": \"symfony\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 5.4.52\"}, {\"status\": \"affected\", \"version\": \"\u003e= 6.0.0-BETA1, \u003c 6.4.40\"}, {\"status\": \"affected\", \"version\": \"\u003e= 7.0.0-BETA1, \u003c 7.4.12\"}, {\"status\": \"affected\", \"version\": \"\u003e= 8.0.0-BETA1, \u003c 8.0.12\"}]}, {\"vendor\": \"symfony\", \"product\": \"yaml\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 5.4.52\"}, {\"status\": \"affected\", \"version\": \"\u003e= 6.0.0-BETA1, \u003c 6.4.40\"}, {\"status\": \"affected\", \"version\": \"\u003e= 7.0.0-BETA1, \u003c 7.4.12\"}, {\"status\": \"affected\", \"version\": \"\u003e= 8.0.0-BETA1, \u003c 8.0.12\"}]}], \"references\": [{\"url\": \"https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4\", \"name\": \"https://github.com/symfony/symfony/security/advisories/GHSA-4qpc-3hr4-r2p4\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a\", \"name\": \"https://github.com/symfony/symfony/commit/e77391b2e4f18821198f010d573674c8ed4a970a\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/symfony/symfony/releases/tag/v5.4.52\", \"name\": \"https://github.com/symfony/symfony/releases/tag/v5.4.52\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/symfony/symfony/releases/tag/v6.4.40\", \"name\": \"https://github.com/symfony/symfony/releases/tag/v6.4.40\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/symfony/symfony/releases/tag/v7.4.12\", \"name\": \"https://github.com/symfony/symfony/releases/tag/v7.4.12\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/symfony/symfony/releases/tag/v8.0.12\", \"name\": \"https://github.com/symfony/symfony/releases/tag/v8.0.12\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\\\\Component\\\\Yaml\\\\Parser resolved YAML collection aliases recursively, allowing a small untrusted YAML input to expand into a multi-gigabyte structure and exhaust memory. This issue is fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-776\", \"description\": \"CWE-776: Improper Restriction of Recursive Entity References in DTDs (\u0027XML Entity Expansion\u0027)\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-07-14T18:48:49.329Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-45304\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-07-14T19:13:39.323Z\", \"dateReserved\": \"2026-05-11T20:14:43.202Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-07-14T18:48:49.329Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.