high · 8.2 No patch yet

Unbounded atom creation from unsigned LogoutResponse status codes in esaml allows atom table exhaustion

CVE-2026-86696 · EEF-CVE-2026-86696 · published 22 Oct 2026

How serious is it

  • Severity: high, CVSS score 8.2 out of 10.
  • No exploit prediction (EPSS) score yet.
  • Not on the CISA list of exploited vulnerabilities.
  • No public exploit in Exploit-DB.

Is your app affected by CVE-2026-86696?

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Who is affected

  • esaml (Hex) >= 0.1.0

How to check

  1. Look for esaml in your lockfile and compare its version with the range above.
  2. Or paste your lockfile into the checker: it lists every package with a known vulnerability, this one included.

How to fix

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  1. No fixed version of esaml yet. Replace or remove it, or apply the workaround in the advisory below.
  2. If a vulnerable version was live, check your logs and rotate the secrets that server could read.

The advisory

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.

Check your whole app

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References

Merged from OSV, CVE List. Last updated 1 Nov 2026. All vulnerabilities · RSS · JSON

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