Vulnerability · Published Oct 22, 2026 · Assigned by EEF
CVE-2026-86696Unbounded atom creation from unsigned LogoutResponse status codes in esaml allows atom table exhaustion
High 8.2
In plain English
A high-severity resource allocation without limits in esaml from arekinath. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).
Official description
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 products (as reported)
Weakness: CWE-770 · Vector: 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
References
- EEF CNA record for CVE-2026-86696 related, third-party-advisory
- OSV record EEF-CVE-2026-86696 related
- Introducing commit be692b5 in handnot2/esaml related
- Introducing commit be692b5 in arekinath/esaml related
- Introducing commit be692b5 in dropbox/esaml related, broken-link