{
  "containers": {
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          "cpes": [
            "cpe:2.3:a:arekinath:esaml:*:*:*:*:*:*:*:*"
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          "defaultStatus": "unaffected",
          "modules": [
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          "packageName": "arekinath/esaml",
          "packageURL": "pkg:github/arekinath/esaml",
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          "programRoutines": [
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            {
              "name": "esaml_cowboy:validate_assertion/2"
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            {
              "name": "esaml_cowboy:validate_logout/2"
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          "repo": "https://github.com/arekinath/esaml",
          "vendor": "arekinath",
          "versions": [
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              "status": "affected",
              "version": "deeb84378d5c82153b470e99d24f77c38afca14a",
              "versionType": "git"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
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          "defaultStatus": "unaffected",
          "modules": [
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          "packageName": "handnot2/esaml",
          "packageURL": "pkg:github/handnot2/esaml",
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          "programRoutines": [
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              "name": "esaml_binding:decode_response/2"
            },
            {
              "name": "esaml_cowboy:validate_assertion/2"
            },
            {
              "name": "esaml_cowboy:validate_logout/2"
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          ],
          "repo": "https://github.com/handnot2/esaml",
          "vendor": "handnot2",
          "versions": [
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              "status": "affected",
              "version": "deeb84378d5c82153b470e99d24f77c38afca14a",
              "versionType": "git"
            }
          ]
        },
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
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            "esaml_cowboy"
          ],
          "packageName": "esaml",
          "packageURL": "pkg:hex/esaml",
          "product": "esaml",
          "programFiles": [
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            "src/esaml_cowboy.erl"
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          "programRoutines": [
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            },
            {
              "name": "esaml_cowboy:validate_assertion/2"
            },
            {
              "name": "esaml_cowboy:validate_logout/2"
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          ],
          "repo": "https://github.com/dropbox/esaml",
          "vendor": "dropbox",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "0.1.0",
              "versionType": "semver"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
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          ],
          "defaultStatus": "unaffected",
          "modules": [
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            "esaml_cowboy"
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          "packageURL": "pkg:github/dropbox/esaml",
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          "programRoutines": [
            {
              "name": "esaml_binding:decode_response/2"
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            {
              "name": "esaml_cowboy:validate_assertion/2"
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            {
              "name": "esaml_cowboy:validate_logout/2"
            }
          ],
          "repo": "https://github.com/dropbox/esaml",
          "vendor": "dropbox",
          "versions": [
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              "lessThan": "*",
              "status": "affected",
              "version": "deeb84378d5c82153b470e99d24f77c38afca14a",
              "versionType": "git"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "2.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "0.1.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "AND"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Quinn Wilton"
        },
        {
          "lang": "en",
          "type": "reporter",
          "value": "Quinn Wilton"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "Jonatan M\u00e4nnchen / EEF"
        }
      ],
      "dateAssigned": "2026-10-08T14:44:30.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
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              "type": "text/html",
              "value": "\u003cp\u003eAllocation of Resources Without Limits or Throttling vulnerability in \u003ccode\u003eesaml_binding\u003c/code\u003e in dropbox esaml allows an unauthenticated attacker to exhaust the Erlang VM atom table and crash the node via a crafted \u003ccode\u003eSAMLResponse\u003c/code\u003e.\u003c/p\u003e\n\u003cp\u003e\u003ccode\u003eesaml_binding:decode_response/2\u003c/code\u003e parses the decoded \u003ccode\u003eSAMLResponse\u003c/code\u003e with \u003ccode\u003exmerl_scan:string/2\u003c/code\u003e, which interns every element name, attribute name, and namespace prefix it reads as a permanent atom. The SAML consume (ACS) and single-logout endpoints call it on unauthenticated requests before any signature check, so one well-formed document with thousands of distinct names mints thousands of atoms while staying inside the 128 KB request body limit. Atoms are never reclaimed and the VM caps the atom table at about one million entries, so a few dozen requests abort the node.\u003c/p\u003e\n\u003cp\u003eThis issue affects esaml: from 0.1.0 onward.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "Allocation of Resources Without Limits or Throttling vulnerability in `esaml_binding` in dropbox esaml allows an unauthenticated attacker to exhaust the Erlang VM atom table and crash the node via a crafted `SAMLResponse`.\n\n`esaml_binding:decode_response/2` parses the decoded `SAMLResponse` with `xmerl_scan:string/2`, which interns every element name, attribute name, and namespace prefix it reads as a permanent atom. The SAML consume (ACS) and single-logout endpoints call it on unauthenticated requests before any signature check, so one well-formed document with thousands of distinct names mints thousands of atoms while staying inside the 128 KB request body limit. Atoms are never reclaimed and the VM caps the atom table at about one million entries, so a few dozen requests abort the node.\n\nThis issue affects esaml: from 0.1.0 onward."
            }
          ],
          "value": "Allocation of Resources Without Limits or Throttling vulnerability in esaml_binding in dropbox esaml allows an unauthenticated attacker to exhaust the Erlang VM atom table and crash the node via a crafted SAMLResponse.\n\nesaml_binding:decode_response/2 parses the decoded SAMLResponse with xmerl_scan:string/2, which interns every element name, attribute name, and namespace prefix it reads as a permanent atom. The SAML consume (ACS) and single-logout endpoints call it on unauthenticated requests before any signature check, so one well-formed document with thousands of distinct names mints thousands of atoms while staying inside the 128 KB request body limit. Atoms are never reclaimed and the VM caps the atom table at about one million entries, so a few dozen requests abort the node.\n\nThis issue affects esaml: from 0.1.0 onward."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-130",
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
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                  "value": "\u003cp\u003eAn unauthenticated attacker posts a small SAML document with thousands of distinct element and attribute names to a service provider\u0027s consume or single-logout endpoint. Each request permanently consumes thousands of atom table entries, and a few dozen requests abort the Erlang VM, denying service to every user of the service provider.\u003c/p\u003e"
                },
                {
                  "base64": false,
                  "type": "text/markdown",
                  "value": "An unauthenticated attacker posts a small SAML document with thousands of distinct element and attribute names to a service provider\u0027s consume or single-logout endpoint. Each request permanently consumes thousands of atom table entries, and a few dozen requests abort the Erlang VM, denying service to every user of the service provider."
                }
              ],
              "value": "An unauthenticated attacker posts a small SAML document with thousands of distinct element and attribute names to a service provider\u0027s consume or single-logout endpoint. Each request permanently consumes thousands of atom table entries, and a few dozen requests abort the Erlang VM, denying service to every user of the service provider."
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "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-770",
              "description": "CWE-770 Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-22T06:58:43.034Z",
        "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "shortName": "EEF"
      },
      "references": [
        {
          "name": "EEF CNA record for CVE-2026-105270",
          "tags": [
            "related",
            "third-party-advisory"
          ],
          "url": "https://cna.erlef.org/cves/CVE-2026-105270.html"
        },
        {
          "name": "OSV record EEF-CVE-2026-105270",
          "tags": [
            "related"
          ],
          "url": "https://osv.dev/vulnerability/EEF-CVE-2026-105270"
        },
        {
          "name": "Introducing commit deeb843 in arekinath/esaml",
          "tags": [
            "related"
          ],
          "url": "https://github.com/arekinath/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a"
        },
        {
          "name": "Introducing commit deeb843 in handnot2/esaml",
          "tags": [
            "related"
          ],
          "url": "https://github.com/handnot2/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a"
        },
        {
          "name": "Introducing commit deeb843 in dropbox/esaml",
          "tags": [
            "related",
            "broken-link"
          ],
          "url": "https://github.com/dropbox/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Unbounded atom creation while parsing SAML messages in esaml allows atom table exhaustion",
      "x_proofOfConcept": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003col\u003e\n\u003cli\u003eBuild a well-formed XML document whose root contains several thousand empty elements with distinct names, each carrying a distinctly named attribute, for example \u003ccode\u003e\u0026lt;p0 a0=\"x\"/\u0026gt;\u003c/code\u003e through \u003ccode\u003e\u0026lt;p4999 a4999=\"x\"/\u0026gt;\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eDeflate and base64-encode it, and post it to the service provider\u0027s SAML consume (ACS) or single-logout endpoint as the \u003ccode\u003eSAMLResponse\u003c/code\u003e form field with \u003ccode\u003eSAMLEncoding\u003c/code\u003e set to the DEFLATE URI. A document with 5,000 elements and 5,000 attributes encodes to about 33 KB.\u003c/li\u003e\n\u003cli\u003e\u003ccode\u003eesaml_binding:decode_response/2\u003c/code\u003e parses it with \u003ccode\u003exmerl_scan:string/2\u003c/code\u003e before any signature check, and the atom table grows by 10,000 entries that are never reclaimed. Repeat with fresh names until the VM aborts.\u003c/li\u003e\n\u003c/ol\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "1. Build a well-formed XML document whose root contains several thousand empty elements with distinct names, each carrying a distinctly named attribute, for example `\u003cp0 a0=\"x\"/\u003e` through `\u003cp4999 a4999=\"x\"/\u003e`.\n2. Deflate and base64-encode it, and post it to the service provider\u0027s SAML consume (ACS) or single-logout endpoint as the `SAMLResponse` form field with `SAMLEncoding` set to the DEFLATE URI. A document with 5,000 elements and 5,000 attributes encodes to about 33 KB.\n3. `esaml_binding:decode_response/2` parses it with `xmerl_scan:string/2` before any signature check, and the atom table grows by 10,000 entries that are never reclaimed. Repeat with fresh names until the VM aborts."
            }
          ],
          "value": "* Build a well-formed XML document whose root contains several thousand empty elements with distinct names, each carrying a distinctly named attribute, for example \u003cp0 a0=\"x\"/\u003e through \u003cp4999 a4999=\"x\"/\u003e.\n* Deflate and base64-encode it, and post it to the service provider\u0027s SAML consume (ACS) or single-logout endpoint as the SAMLResponse form field with SAMLEncoding set to the DEFLATE URI. A document with 5,000 elements and 5,000 attributes encodes to about 33 KB.\n* esaml_binding:decode_response/2 parses it with xmerl_scan:string/2 before any signature check, and the atom table grows by 10,000 entries that are never reclaimed. Repeat with fresh names until the VM aborts."
        }
      ],
      "x_technicalAnalysis": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
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              "value": "\u003cp\u003e\u003cstrong\u003e1. Input.\u003c/strong\u003e The SAML consume (ACS) and single-logout endpoints in \u003ccode\u003eesaml_cowboy\u003c/code\u003e read the request body, capped at 128 KB, and pass the \u003ccode\u003eSAMLResponse\u003c/code\u003e form field to \u003ccode\u003eesaml_binding:decode_response/2\u003c/code\u003e. Both the DEFLATE clause and the default clause end in \u003ccode\u003exmerl_scan:string/2\u003c/code\u003e with \u003ccode\u003enamespace_conformant\u003c/code\u003e set.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Interning.\u003c/strong\u003e \u003ccode\u003exmerl_scan\u003c/code\u003e converts every element name, attribute name, and namespace prefix it tokenizes into an atom with \u003ccode\u003elist_to_atom/1\u003c/code\u003e, and the same happens for each namespace local name in \u003ccode\u003eexpanded_name/4\u003c/code\u003e. A well-formed document with many distinct names therefore mints one permanent atom per name. Repetitive names deflate well, so a document with ten thousand distinct names fits in a few tens of kilobytes on the wire.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3. Exhaustion before any check.\u003c/strong\u003e Signature verification and assertion validation run on the parsed document afterward, so the atoms are minted whether or not the document is a valid or signed SAML message. Atoms are never garbage collected and the VM aborts when the atom table reaches its limit of about one million entries, so a few dozen requests take the node down.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "**1. Input.** The SAML consume (ACS) and single-logout endpoints in `esaml_cowboy` read the request body, capped at 128 KB, and pass the `SAMLResponse` form field to `esaml_binding:decode_response/2`. Both the DEFLATE clause and the default clause end in `xmerl_scan:string/2` with `namespace_conformant` set.\n\n**2. Interning.** `xmerl_scan` converts every element name, attribute name, and namespace prefix it tokenizes into an atom with `list_to_atom/1`, and the same happens for each namespace local name in `expanded_name/4`. A well-formed document with many distinct names therefore mints one permanent atom per name. Repetitive names deflate well, so a document with ten thousand distinct names fits in a few tens of kilobytes on the wire.\n\n**3. Exhaustion before any check.** Signature verification and assertion validation run on the parsed document afterward, so the atoms are minted whether or not the document is a valid or signed SAML message. Atoms are never garbage collected and the VM aborts when the atom table reaches its limit of about one million entries, so a few dozen requests take the node down."
            }
          ],
          "value": "1. Input. The SAML consume (ACS) and single-logout endpoints in esaml_cowboy read the request body, capped at 128 KB, and pass the SAMLResponse form field to esaml_binding:decode_response/2. Both the DEFLATE clause and the default clause end in xmerl_scan:string/2 with namespace_conformant set.\n\n2. Interning. xmerl_scan converts every element name, attribute name, and namespace prefix it tokenizes into an atom with list_to_atom/1, and the same happens for each namespace local name in expanded_name/4. A well-formed document with many distinct names therefore mints one permanent atom per name. Repetitive names deflate well, so a document with ten thousand distinct names fits in a few tens of kilobytes on the wire.\n\n3. Exhaustion before any check. Signature verification and assertion validation run on the parsed document afterward, so the atoms are minted whether or not the document is a valid or signed SAML message. Atoms are never garbage collected and the VM aborts when the atom table reaches its limit of about one million entries, so a few dozen requests take the node down."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
    "assignerShortName": "EEF",
    "cveId": "CVE-2026-105270",
    "datePublished": "2026-10-22T06:58:43.034Z",
    "dateReserved": "2026-10-07T22:15:01.882Z",
    "dateUpdated": "2026-10-22T06:58:43.034Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}