CVE-2026-86696
HIGH 8.2Allocation 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.
Severe if exploited (CVSS 8.2), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 38th percentile
Impact if exploited
8.2CVSS 4.0 · HIGH
- ConfidentialityNone
- IntegrityNone
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ⚠Requirements: Specific conditions must be present
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
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Data snapshot:
Weakness (CWE)
- CWE-770: Allocation of Resources Without Limits or Throttling
CVSS 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 and research data (JSON)
All CVSS metrics
- HIGH 8.2 v4.0 · CNA Primary
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 - HIGH 8.2 v4.0 · NVD Secondary
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
References
Advisories
- https://cna.erlef.org/cves/CVE-2026-86696.html CVE record · EEF · Updated 2026-10-22T06:59:07.680Z
NVD · CVE-2026-86696 · Updated 2026-10-22T16:58:51.997 - https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-108051 EUVD · EUVD-2026-108051
Technical & other
- https://osv.dev/vulnerability/EEF-CVE-2026-86696 CVE record · EEF · Updated 2026-10-22T06:59:07.680Z
NVD · CVE-2026-86696 · Updated 2026-10-22T16:58:51.997 - https://github.com/handnot2/esaml/commit/be692b56245071899757afa7ef47e43593d3de96 CVE record · EEF · Updated 2026-10-22T06:59:07.680Z
NVD · CVE-2026-86696 · Updated 2026-10-22T16:58:51.997 - https://github.com/arekinath/esaml/commit/be692b56245071899757afa7ef47e43593d3de96 CVE record · EEF · Updated 2026-10-22T06:59:07.680Z
NVD · CVE-2026-86696 · Updated 2026-10-22T16:58:51.997 - https://github.com/dropbox/esaml/commit/be692b56245071899757afa7ef47e43593d3de96 CVE record · EEF · Updated 2026-10-22T06:59:07.680Z
NVD · CVE-2026-86696 · Updated 2026-10-22T16:58:51.997