Unbounded SAML message decompression in esaml allows memory exhaustion
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The esaml library, a Erlang implementation of SAML used for single sign-on in web applications, is affected. An unauthenticated attacker can send a small, specially crafted compressed SAML message that expands to a huge size during processing, causing the server to run out of memory and crash.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original 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.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- handnot2/esaml
From deeb84378d5c82153b470e99d24f77c38afca14a · fixed in *
- arekinath/esaml
From deeb84378d5c82153b470e99d24f77c38afca14a · fixed in *
- esaml
From 0.1.0 · fixed in *
- dropbox/esaml
From deeb84378d5c82153b470e99d24f77c38afca14a · fixed in *
- esamlHex
From 0.1.0