[ CVE-2026-93471 · Published 22 Oct 2026 ]
Vulnerability in handnot2 esaml
[ Description ]Official description
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. 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. This issue affects esaml: from 0.1.0 onward.
[ Fixes ]Fixes and patches
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.