CVE-2026-93471 Unbounded SAML message decompression in esaml allows memory exhaustion
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-93471?
CVE-2026-93471 is a high-severity vulnerability in arekinath esaml, published on 22 Oct 2026.
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.
Weakness: CWE-409
Which versions are affected by CVE-2026-93471?
1 open source package ship an affected version, including esaml.
| Package | Affected | Fixed in |
|---|---|---|
esaml Hex | From 0.1.0 | None |
How do I fix CVE-2026-93471?
No fix has been published for CVE-2026-93471 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-93471 being exploited?
There is no known exploitation of CVE-2026-93471 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-93471, GHSA-3gv4-v3m4-w3vp.