{"id":"CVE-2026-93471","summary":"Unbounded SAML message decompression in esaml allows memory exhaustion","details":"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.","aliases":["EEF-CVE-2026-93471"],"modified":"2026-10-24T02:48:01.662554844Z","published":"2026-10-22T06:59:24.029Z","database_specific":{"cna_assigner":"EEF","cwe_ids":["CWE-409"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93471.json","unresolved_ranges":[{"extracted_events":[{"strategy":"StandardRange","range":[{"introduced":"deeb84378d5c82153b470e99d24f77c38afca14a"},{"fixed":"*"},{"introduced":"deeb84378d5c82153b470e99d24f77c38afca14a"},{"fixed":"*"},{"introduced":"0.1.0"},{"fixed":"*"},{"introduced":"deeb84378d5c82153b470e99d24f77c38afca14a"},{"fixed":"*"}],"source":"AFFECTED_FIELD"}]}]},"references":[{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-93471"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://cna.erlef.org/cves/CVE-2026-93471.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93471.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93471"},{"type":"FIX","url":"https://github.com/arekinath/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a"},{"type":"FIX","url":"https://github.com/dropbox/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a"},{"type":"FIX","url":"https://github.com/handnot2/esaml/commit/deeb84378d5c82153b470e99d24f77c38afca14a"},{"type":"PACKAGE","url":"https://github.com/arekinath/esaml"},{"type":"PACKAGE","url":"https://github.com/dropbox/esaml"},{"type":"PACKAGE","url":"https://github.com/handnot2/esaml"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/arekinath/esaml","events":[{"introduced":"0"},{"fixed":"deeb84378d5c82153b470e99d24f77c38afca14a"}],"database_specific":{"extracted_events":[{"range":[{"fixed":"deeb84378d5c82153b470e99d24f77c38afca14a"}],"source":"REFERENCES_COMMIT"}]}},{"type":"GIT","repo":"https://github.com/handnot2/esaml","events":[{"introduced":"0"},{"fixed":"deeb84378d5c82153b470e99d24f77c38afca14a"}],"database_specific":{"extracted_events":[{"source":"REFERENCES_COMMIT","range":[{"fixed":"deeb84378d5c82153b470e99d24f77c38afca14a"}]}]}}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-93471.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V4","score":"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"}]}