# CVE-2026-93471: Dropbox esaml data amplification denial of service

Source: https://junglewise.ai/threats/cve-2026-93471-improper-handling-of-highly-compressed-data-data-amplification-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-22. Updated: 2026-10-22  
License: CC BY 4.0 with a link back

CVE-2026-93471 · Severity: info · Published 2026-10-22

Dropbox esaml is a library that handles SAML authentication for single sign-on systems. An unauthenticated attacker can send a specially crafted SAML request that decompresses to an enormous size, exhausting server memory and crashing the system. This vulnerability affects any service using esaml for authentication.

Technologies: [Dropbox Esaml](https://junglewise.ai/threats/technologies/dropbox-esaml). Vendors: [Dropbox](https://junglewise.ai/threats/vendors/dropbox).

## Quick answers

**Is CVE-2026-93471 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-93471 being exploited in the wild.

**How severe is CVE-2026-93471?** Informational severity, published 22 October 2026.

**Which products and versions are affected?** Dropbox Esaml 0.1.0 and later.

**Is there a fix for CVE-2026-93471?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-93471 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-93471?** Check whether you run Dropbox Esaml at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The esaml_binding:decode_response/2 function base64-decodes and inflates a SAML response using zlib without limiting decompression output, then converts the result to a charlist before parsing. The vulnerability is exposed on SAML ACS (assertion consumer service) and single-logout endpoints which accept unauthenticated requests by design. An attacker can craft a deflate stream with a compression ratio near 1000:1, causing tens of kilobytes of input to expand to gigabytes, exhausting heap memory and crashing the Erlang VM.

## Affected products

- Dropbox esaml 0.1.0 and later

## Timeline

- 2026-10-22: disclosed

## References

- [https://github.com/](https://github.com/)
- [https://repo.hex.pm/](https://repo.hex.pm/)

## Related threats

- [Dropbox esaml unthrottled atom creation in LogoutResponse](https://junglewise.ai/threats/cve-2026-86696-allocation-of-resources-without-limits-or-throttling)
- [Dropbox esaml atom table exhaustion in SAMLResponse parsing](https://junglewise.ai/threats/cve-2026-105270-allocation-of-resources-without-limits-or-throttling)