CVE-2026-86696 json
Unbounded atom creation from unsigned LogoutResponse status codes in esaml allows atom table exhaustion
published 2026-10-22 17 d ago modified 2026-10-30 9 d ago also EEF-CVE-2026-86696 , EUVD-2026-108051
- cvss
- 8.2
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 51%
- public exploits
- 0
- none known
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_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.
Patch / fix
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 9 d ago
Exploit prediction
0.66% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- cna.erlef.org https://cna.erlef.org/cves/CVE-2026-86696.html referenced PoC, tagged "exploit" by a source, unverified
- osv.dev https://osv.dev/vulnerability/EEF-CVE-2026-86696 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.2 | 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 |
| CNA | 4.0 | 8.2 | 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 |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| hex | esaml | >=0.1.0 |
no fix listed |
Affected products
- handnot2 esaml
- arekinath esaml
- dropbox esaml
Classification
- Weakness
-
- CWE-770 Allocation of Resources Without Limits or Throttling
References
-
github.com
/handnot2/esaml/commit/be692b56245071899757afa7ef47e43593d3de96
related, web
-
github.com
/arekinath/esaml/commit/be692b56245071899757afa7ef47e43593d3de96
related, web
-
github.com
/dropbox/esaml/commit/be692b56245071899757afa7ef47e43593d3de96
related, broken-link, web
-
cna.erlef.org
/cves/CVE-2026-86696.html
related, third-party-advisory, exploit, web
-
osv.dev
/vulnerability/EEF-CVE-2026-86696
related, exploit
-
hex.pm
/packages/esaml
package
Sources
- CVE List CVE-2026-86696
- NVD CVE-2026-86696
- OSV EEF-CVE-2026-86696
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