CVE-2026-93471
Unbounded SAML message decompression in esaml allows memory exhaustion
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.
INFO
Published Date :
Oct. 22, 2026, 6:59 a.m.
Last Modified :
Oct. 22, 2026, 6:59 a.m.
Remotely Exploit :
Yes !
Source :
EEF
Affected Products
The following products are affected by CVE-2026-93471
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Apply bounds to inflate operations.
- Validate input size before decompression.
- Update esaml to a version with bounds.
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CVE-2026-93471 vulnerability anywhere in the article.