---
id: CVE-2026-65628
title: >-
  Infinite recursion (CPU denial-of-service) in JOSE.JWK.shared_secret/2 on
  mismatched key types
summary: >-
  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-…
severity: medium
cvss: 5.9
cvssVector: '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'
cvssSource: cna
cwe:
  - CWE-674
vendor: potatosalad
product: jose
affected:
  - jose >= 1.5.0 < 1.11.13
  - >-
    potatosalad/erlang-jose >= 7b80b9f55b9898e1a6901ce136061b241b021d7c <
    26182a7de63b91550035d3f08741f7d17f1f675a
published: '2026-10-26'
updated: '2026-10-26'
sourceUpdated: '2026-10-26T19:53:27.625Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-65628'
references:
  - url: >-
      https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-fpj2-9h59-32pp
  - url: 'https://cna.erlef.org/cves/CVE-2026-65628.html'
    label: EEF CNA record for CVE-2026-65628
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-65628'
    label: OSV record EEF-CVE-2026-65628
  - url: >-
      https://github.com/potatosalad/erlang-jose/commit/7b80b9f55b9898e1a6901ce136061b241b021d7c
    label: Introducing commit 7b80b9f in potatosalad/erlang-jose
  - url: >-
      https://github.com/potatosalad/erlang-jose/commit/26182a7de63b91550035d3f08741f7d17f1f675a
    label: Fix commit 26182a7 in potatosalad/erlang-jose
tags:
  - cve.org
ingestedAt: '2026-10-26T20:39:42.625Z'
epss: 0.00136
epssPercentile: 0.03018
---

## Overview

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.

## Affected

- `jose >= 1.5.0 < 1.11.13`
- `potatosalad/erlang-jose >= 7b80b9f55b9898e1a6901ce136061b241b021d7c < 26182a7de63b91550035d3f08741f7d17f1f675a`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

### Workarounds

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.