---
cve: "CVE-2026-65628"
severity: "MEDIUM"
cvss: 5.9
epss: ""
vendor: "potatosalad"
kev: false
exploited: false
published: "2026-10-26 20:17:58"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-10-29T17:30:38+01:00"
---

# CVE-2026-65628

> 5.9 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **EEF**
- State: PUBLISHED
- Stand: 2026-10-26 19:53:27
- CNA-CVSS: **5.9** (`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`)

## CVSS-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Schwachstellen-Klasse

- **CWE-674** — Uncontrolled Recursion
  The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.

## Angriffsmuster (CAPEC)

- [CAPEC-230 — Serialized Data with Nested Payloads](https://capec.mitre.org/data/definitions/230.html) _(Severity: High)_
- [CAPEC-231 — Oversized Serialized Data Payloads](https://capec.mitre.org/data/definitions/231.html) _(Severity: High)_

## Patch verfügbar (OSV)

- 26182a7de63b91550035d3f08741f7d17f1f675a (Commit)
- 7b80b9f55b9898e1a6901ce136061b241b021d7c (Commit)

## Referenzen

- <https://github.com/potatosalad/erlang-jose/security/advisories/GHSA-fpj2-9h59-32pp>
- <https://cna.erlef.org/cves/CVE-2026-65628.html>
- <https://osv.dev/vulnerability/EEF-CVE-2026-65628>
- <https://github.com/potatosalad/erlang-jose/commit/7b80b9f55b9898e1a6901ce136061b241b021d7c>
- <https://github.com/potatosalad/erlang-jose/commit/26182a7de63b91550035d3f08741f7d17f1f675a>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-65628/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_