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\"affected\": [{\"cpes\": [\"cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/handnot2/esaml\", \"vendor\": \"handnot2\", \"modules\": [\"esaml_binding\", \"esaml_cowboy\"], \"product\": \"esaml\", \"versions\": [{\"status\": \"affected\", \"version\": \"deeb84378d5c82153b470e99d24f77c38afca14a\", \"lessThan\": \"*\", \"versionType\": \"git\"}], \"packageURL\": \"pkg:github/handnot2/esaml\", \"packageName\": \"handnot2/esaml\", \"programFiles\": [\"src/esaml_binding.erl\", \"src/esaml_cowboy.erl\"], \"collectionURL\": \"https://github.com\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"esaml_binding:decode_response/2\"}, {\"name\": \"esaml_cowboy:validate_assertion/2\"}, {\"name\": \"esaml_cowboy:validate_logout/2\"}]}, {\"cpes\": [\"cpe:2.3:a:arekinath:esaml:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/arekinath/esaml\", \"vendor\": \"arekinath\", \"modules\": [\"esaml_binding\", \"esaml_cowboy\"], \"product\": \"esaml\", \"versions\": [{\"status\": \"affected\", \"version\": \"deeb84378d5c82153b470e99d24f77c38afca14a\", \"lessThan\": \"*\", \"versionType\": \"git\"}], \"packageURL\": \"pkg:github/arekinath/esaml\", \"packageName\": \"arekinath/esaml\", \"programFiles\": [\"src/esaml_binding.erl\", \"src/esaml_cowboy.erl\"], \"collectionURL\": \"https://github.com\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"esaml_binding:decode_response/2\"}, {\"name\": \"esaml_cowboy:validate_assertion/2\"}, {\"name\": \"esaml_cowboy:validate_logout/2\"}]}, {\"cpes\": [\"cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/dropbox/esaml\", \"vendor\": \"dropbox\", \"modules\": [\"esaml_binding\", \"esaml_cowboy\"], \"product\": \"esaml\", \"versions\": [{\"status\": \"affected\", \"version\": \"0.1.0\", \"lessThan\": \"*\", \"versionType\": \"semver\"}], \"packageURL\": \"pkg:hex/esaml\", \"packageName\": \"esaml\", \"programFiles\": [\"src/esaml_binding.erl\", \"src/esaml_cowboy.erl\"], \"collectionURL\": \"https://repo.hex.pm\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"esaml_binding:decode_response/2\"}, {\"name\": \"esaml_cowboy:validate_assertion/2\"}, {\"name\": \"esaml_cowboy:validate_logout/2\"}]}, {\"cpes\": [\"cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*\"], \"repo\": \"https://github.com/dropbox/esaml\", \"vendor\": \"dropbox\", \"modules\": [\"esaml_binding\", \"esaml_cowboy\"], \"product\": \"esaml\", \"versions\": [{\"status\": \"affected\", \"version\": \"deeb84378d5c82153b470e99d24f77c38afca14a\", \"lessThan\": \"*\", \"versionType\": \"git\"}], \"packageURL\": \"pkg:github/dropbox/esaml\", \"packageName\": \"dropbox/esaml\", \"programFiles\": [\"src/esaml_binding.erl\", \"src/esaml_cowboy.erl\"], \"collectionURL\": \"https://github.com\", \"defaultStatus\": \"unaffected\", \"programRoutines\": [{\"name\": \"esaml_binding:decode_response/2\"}, {\"name\": \"esaml_cowboy:validate_assertion/2\"}, {\"name\": \"esaml_cowboy:validate_logout/2\"}]}], \"references\": [{\"url\": \"https://cna.erlef.org/cves/CVE-2026-93471.html\", \"name\": \"EEF CNA record for CVE-2026-93471\", \"tags\": [\"related\", \"third-party-advisory\"]}, {\"url\": \"https://osv.dev/vulnerability/EEF-CVE-2026-93471\", \"name\": \"OSV record EEF-CVE-2026-93471\", \"tags\": [\"related\"]}, {\"url\": \"https://github.com/handnot2/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a\", \"name\": \"Introducing commit deeb843 in handnot2/esaml\", \"tags\": [\"related\"]}, {\"url\": \"https://github.com/arekinath/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a\", \"name\": \"Introducing commit deeb843 in arekinath/esaml\", \"tags\": [\"related\"]}, {\"url\": \"https://github.com/dropbox/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a\", \"name\": \"Introducing commit deeb843 in dropbox/esaml\", \"tags\": [\"related\", \"broken-link\"]}], \"dateAssigned\": \"2026-10-06T10:25:40.000Z\", \"descriptions\": [{\"lang\": \"en\", \"value\": \"Improper Handling of Highly Compressed Data (Data Amplification) in esaml_binding in dropbox esaml allows an unauthenticated attacker to exhaust server memory and crash the Erlang VM via a crafted compressed SAMLResponse.\\n\\nesaml_binding:decode_response/2 base64-decodes the attacker-supplied SAMLResponse, inflates it with zlib:unzip/1 with no bound on the output, then converts the result to a charlist with binary_to_list/1 before parsing. This runs on the SAML consume (ACS) and single-logout endpoints, which accept unauthenticated requests by design, and it runs before any signature check. A small deflate stream reaches a compression ratio near 1000 to 1, so a request body of tens of kilobytes inflates to hundreds of megabytes and then to several gigabytes of list heap, so a few requests exhaust memory and take the node down.\\n\\nThis issue affects esaml: from 0.1.0 onward.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003eImproper Handling of Highly Compressed Data (Data Amplification) in \u003ccode\u003eesaml_binding\u003c/code\u003e in dropbox esaml allows an unauthenticated attacker to exhaust server memory and crash the Erlang VM via a crafted compressed \u003ccode\u003eSAMLResponse\u003c/code\u003e.\u003c/p\u003e\\n\u003cp\u003e\u003ccode\u003eesaml_binding:decode_response/2\u003c/code\u003e base64-decodes the attacker-supplied \u003ccode\u003eSAMLResponse\u003c/code\u003e, inflates it with \u003ccode\u003ezlib:unzip/1\u003c/code\u003e with no bound on the output, then converts the result to a charlist with \u003ccode\u003ebinary_to_list/1\u003c/code\u003e before parsing. This runs on the SAML consume (ACS) and single-logout endpoints, which accept unauthenticated requests by design, and it runs before any signature check. A small deflate stream reaches a compression ratio near 1000 to 1, so a request body of tens of kilobytes inflates to hundreds of megabytes and then to several gigabytes of list heap, so a few requests exhaust memory and take the node down.\u003c/p\u003e\\n\u003cp\u003eThis issue affects esaml: from 0.1.0 onward.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"Improper Handling of Highly Compressed Data (Data Amplification) in `esaml_binding` in dropbox esaml allows an unauthenticated attacker to exhaust server memory and crash the Erlang VM via a crafted compressed `SAMLResponse`.\\n\\n`esaml_binding:decode_response/2` base64-decodes the attacker-supplied `SAMLResponse`, inflates it with `zlib:unzip/1` with no bound on the output, then converts the result to a charlist with `binary_to_list/1` before parsing. This runs on the SAML consume (ACS) and single-logout endpoints, which accept unauthenticated requests by design, and it runs before any signature check. A small deflate stream reaches a compression ratio near 1000 to 1, so a request body of tens of kilobytes inflates to hundreds of megabytes and then to several gigabytes of list heap, so a few requests exhaust memory and take the node down.\\n\\nThis issue affects esaml: from 0.1.0 onward.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-409\", \"description\": \"CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)\"}]}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:a:handnot2:esaml:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"2.0.0\"}, {\"criteria\": \"cpe:2.3:a:dropbox:esaml:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"0.1.0\"}], \"operator\": \"OR\"}], \"operator\": \"AND\"}], \"providerMetadata\": {\"orgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"shortName\": \"EEF\", \"dateUpdated\": \"2026-10-22T06:59:24.029Z\"}, \"x_proofOfConcept\": [{\"lang\": \"en\", \"value\": \"* Build a SAMLResponse as the base64 of a raw deflate stream of a long run of identical bytes (for example 60 MB of zero bytes), which encodes to roughly 79 KB on the wire.\\n* Post it to the service provider\u0027s SAML consume (ACS) endpoint as the SAMLResponse form field, with SAMLEncoding set to the DEFLATE URI, or omitted to take the default clause.\\n* esaml_binding:decode_response/2 inflates the stream and converts it to a charlist before any signature check. A single request spikes the Erlang VM by several gigabytes. Repeat to exhaust memory and crash the node.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003col\u003e\\n\u003cli\u003eBuild a \u003ccode\u003eSAMLResponse\u003c/code\u003e as the base64 of a raw deflate stream of a long run of identical bytes (for example 60 MB of zero bytes), which encodes to roughly 79 KB on the wire.\u003c/li\u003e\\n\u003cli\u003ePost it to the service provider\u0027s SAML consume (ACS) endpoint as the \u003ccode\u003eSAMLResponse\u003c/code\u003e form field, with \u003ccode\u003eSAMLEncoding\u003c/code\u003e set to the DEFLATE URI, or omitted to take the default clause.\u003c/li\u003e\\n\u003cli\u003e\u003ccode\u003eesaml_binding:decode_response/2\u003c/code\u003e inflates the stream and converts it to a charlist before any signature check. A single request spikes the Erlang VM by several gigabytes. Repeat to exhaust memory and crash the node.\u003c/li\u003e\\n\u003c/ol\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"1. Build a `SAMLResponse` as the base64 of a raw deflate stream of a long run of identical bytes (for example 60 MB of zero bytes), which encodes to roughly 79 KB on the wire.\\n2. Post it to the service provider\u0027s SAML consume (ACS) endpoint as the `SAMLResponse` form field, with `SAMLEncoding` set to the DEFLATE URI, or omitted to take the default clause.\\n3. `esaml_binding:decode_response/2` inflates the stream and converts it to a charlist before any signature check. A single request spikes the Erlang VM by several gigabytes. Repeat to exhaust memory and crash the node.\", \"base64\": false}]}], \"x_technicalAnalysis\": [{\"lang\": \"en\", \"value\": \"1. Input. The SAML consume (ACS) and single-logout endpoints read the request body and pass the SAMLResponse form field to esaml_binding:decode_response/2. The attacker\u0027s SAMLEncoding field selects the clause. Both clauses inflate: the explicit DEFLATE clause, and the default clause, which tries zlib:unzip/1 inside a catch whenever the body is not plain XML.\\n\\n2. Unbounded inflate. decode_response/2 evaluates binary_to_list(zlib:unzip(base64:decode(SAMLResponse))). zlib:unzip/1 inflates the whole stream in one call with no cap on output size, and binary_to_list/1 then expands the inflated binary to a charlist, which costs about 16 bytes of heap per byte on a 64-bit VM.\\n\\n3. Exhaustion before any check. All of this happens before xmerl_scan parses the document and before esaml_sp verifies any signature. A deflate stream of a long run of identical bytes reaches a ratio near 1000 to 1, so a request body of tens of kilobytes produces hundreds of megabytes of binary and then several gigabytes of list heap. A few concurrent requests exhaust memory and crash the node.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"\u003cp\u003e\u003cstrong\u003e1. Input.\u003c/strong\u003e The SAML consume (ACS) and single-logout endpoints read the request body and pass the \u003ccode\u003eSAMLResponse\u003c/code\u003e form field to \u003ccode\u003eesaml_binding:decode_response/2\u003c/code\u003e. The attacker\u0027s \u003ccode\u003eSAMLEncoding\u003c/code\u003e field selects the clause. Both clauses inflate: the explicit DEFLATE clause, and the default clause, which tries \u003ccode\u003ezlib:unzip/1\u003c/code\u003e inside a \u003ccode\u003ecatch\u003c/code\u003e whenever the body is not plain XML.\u003c/p\u003e\\n\u003cp\u003e\u003cstrong\u003e2. Unbounded inflate.\u003c/strong\u003e \u003ccode\u003edecode_response/2\u003c/code\u003e evaluates \u003ccode\u003ebinary_to_list(zlib:unzip(base64:decode(SAMLResponse)))\u003c/code\u003e. \u003ccode\u003ezlib:unzip/1\u003c/code\u003e inflates the whole stream in one call with no cap on output size, and \u003ccode\u003ebinary_to_list/1\u003c/code\u003e then expands the inflated binary to a charlist, which costs about 16 bytes of heap per byte on a 64-bit VM.\u003c/p\u003e\\n\u003cp\u003e\u003cstrong\u003e3. Exhaustion before any check.\u003c/strong\u003e All of this happens before \u003ccode\u003exmerl_scan\u003c/code\u003e parses the document and before \u003ccode\u003eesaml_sp\u003c/code\u003e verifies any signature. A deflate stream of a long run of identical bytes reaches a ratio near 1000 to 1, so a request body of tens of kilobytes produces hundreds of megabytes of binary and then several gigabytes of list heap. A few concurrent requests exhaust memory and crash the node.\u003c/p\u003e\", \"base64\": false}, {\"type\": \"text/markdown\", \"value\": \"**1. Input.** The SAML consume (ACS) and single-logout endpoints read the request body and pass the `SAMLResponse` form field to `esaml_binding:decode_response/2`. The attacker\u0027s `SAMLEncoding` field selects the clause. Both clauses inflate: the explicit DEFLATE clause, and the default clause, which tries `zlib:unzip/1` inside a `catch` whenever the body is not plain XML.\\n\\n**2. Unbounded inflate.** `decode_response/2` evaluates `binary_to_list(zlib:unzip(base64:decode(SAMLResponse)))`. `zlib:unzip/1` inflates the whole stream in one call with no cap on output size, and `binary_to_list/1` then expands the inflated binary to a charlist, which costs about 16 bytes of heap per byte on a 64-bit VM.\\n\\n**3. Exhaustion before any check.** All of this happens before `xmerl_scan` parses the document and before `esaml_sp` verifies any signature. A deflate stream of a long run of identical bytes reaches a ratio near 1000 to 1, so a request body of tens of kilobytes produces hundreds of megabytes of binary and then several gigabytes of list heap. A few concurrent requests exhaust memory and crash the node.\", \"base64\": false}]}]}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-93471\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-10-30T18:07:07.385Z\", \"dateReserved\": \"2026-10-06T08:45:01.518Z\", \"assignerOrgId\": \"6b3ad84c-e1a6-4bf7-a703-f496b71e49db\", \"datePublished\": \"2026-10-22T06:59:24.029Z\", \"assignerShortName\": \"EEF\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
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