---
id: CVE-2026-86696
title: >-
  Unbounded atom creation from unsigned LogoutResponse status codes in esaml
  allows atom table exhaustion
summary: >-
  Allocation of Resources Without Limits or Throttling vulnerability in esaml in
  dropbox esaml allows an unauthenticated attacker to exhaust the Erlang VM atom
  table and crash the node via unsigned LogoutResponse messages.


  esaml:status_co…
severity: high
cvss: 8.2
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-770
vendor: handnot2
product: handnot2/esaml
affected:
  - handnot2/esaml >= be692b56245071899757afa7ef47e43593d3de96 < *
  - arekinath/esaml >= be692b56245071899757afa7ef47e43593d3de96 < *
  - esaml >= 0.1.0 < *
  - dropbox/esaml >= be692b56245071899757afa7ef47e43593d3de96 < *
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T06:59:07.680Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-86696'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-86696.html'
    label: EEF CNA record for CVE-2026-86696
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-86696'
    label: OSV record EEF-CVE-2026-86696
  - url: >-
      https://github.com/handnot2/esaml/commit/be692b56245071899757afa7ef47e43593d3de96
    label: Introducing commit be692b5 in handnot2/esaml
  - url: >-
      https://github.com/arekinath/esaml/commit/be692b56245071899757afa7ef47e43593d3de96
    label: Introducing commit be692b5 in arekinath/esaml
  - url: >-
      https://github.com/dropbox/esaml/commit/be692b56245071899757afa7ef47e43593d3de96
    label: Introducing commit be692b5 in dropbox/esaml
tags:
  - cve.org
ingestedAt: '2026-10-22T07:32:31.141Z'
---

## Overview

Allocation of Resources Without Limits or Throttling vulnerability in esaml in dropbox esaml allows an unauthenticated attacker to exhaust the Erlang VM atom table and crash the node via unsigned LogoutResponse messages.

esaml:status_code_map/1 in src/esaml.erl maps any StatusCode value it does not recognize to an atom with list_to_atom/1 on the last colon-separated segment of the URN. esaml_sp:validate_logout_response/2 verifies a signature only when the message carries one, so an unsigned LogoutResponse posted to the single-logout endpoint reaches esaml:decode_logout_response/1 and mints one permanent atom per distinct status value. Atoms are never reclaimed and the VM caps the atom table at about one million entries, so an attacker who posts that many distinct values aborts the node.

This issue affects esaml: from 0.1.0 onward.

## Affected

- `handnot2/esaml >= be692b56245071899757afa7ef47e43593d3de96 < *`
- `arekinath/esaml >= be692b56245071899757afa7ef47e43593d3de96 < *`
- `esaml >= 0.1.0 < *`
- `dropbox/esaml >= be692b56245071899757afa7ef47e43593d3de96 < *`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.