CVE-2026-65628

Infinite recursion (CPU denial-of-service) in JOSE.JWK.shared_secret/2 on mismatched key types

Published Oct 26, 2026 CVSS 4.0 · 5.9 Medium EPSS < 1% KEV · Not listed
Description
jose_jwk:shared_secret/2 (exposed in Elixir as JOSE.JWK.shared_secret/2) derives an ECDH shared secret from two JWKs. Its first function clause only matches when both JWKs carry the same key type (kty) module, and its fallback clause re-invokes itself as shared_secret(from(YourJWK), from(MyJWK)). Because from/1 returns an already-parsed jose_jwk record unchanged, passing two JWKs whose key types differ (for example an EC key and an RSA key) makes the fallback clause re-enter with identical arguments, producing an unbounded tail-recursive loop that never returns and never crashes.

An application that derives a shared secret from an externally supplied peer public key without first checking that the peer key's type and curve match its own key can be driven into this loop by an attacker-controlled JWK, pinning an Erlang scheduler at 100% CPU. Repeated requests exhaust the available schedulers, resulting in a denial of service.

This issue affects jose: from 1.5.0 before 1.11.13.

Remediation

Vendor Workaround

Before calling JOSE.JWK.shared_secret/2, verify that the externally supplied peer key's type (kty) and curve match your own key, and reject any key whose type does not match before attempting derivation.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description jose_jwk:shared_secret/2 (exposed in Elixir as JOSE.JWK.shared_secret/2) derives an ECDH shared secret from two JWKs. Its first function clause only matches when both JWKs carry the same key type (kty) module, and its fallback clause re-invokes itself as shared_secret(from(YourJWK), from(MyJWK)). Because from/1 returns an already-parsed jose_jwk record unchanged, passing two JWKs whose key types differ (for example an EC key and an RSA key) makes the fallback clause re-enter with identical arguments, producing an unbounded tail-recursive loop that never returns and never crashes. An application that derives a shared secret from an externally supplied peer public key without first checking that the peer key's type and curve match its own key can be driven into this loop by an attacker-controlled JWK, pinning an Erlang scheduler at 100% CPU. Repeated requests exhaust the available schedulers, resulting in a denial of service. This issue affects jose: from 1.5.0 before 1.11.13.
Title Infinite recursion (CPU denial-of-service) in JOSE.JWK.shared_secret/2 on mismatched key types
First Time appeared Potatosalad
Potatosalad jose
Weaknesses CWE-674
CPEs cpe:2.3:a:potatosalad:jose:*:*:*:*:*:*:*:*
Vendors & Products Potatosalad
Potatosalad jose
References
Metrics cvssV4_0

{'score': 5.9, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
EEF
Published
Updated
Nov 2, 2026, 9:29 PM
Reserved
Jul 22, 2026, 1:58 PM
Status
Deferred
Published
Oct 26, 2026, 8:17 PM
Modified
Nov 2, 2026, 10:17 PM