---
cve: "CVE-2026-73564"
severity: "HIGH"
cvss: 8.7
epss: "38%"
vendor: "fatedier"
kev: false
exploited: false
published: "2026-08-13 18:18:18"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-19T18:54:01+02:00"
---

# CVE-2026-73564

> 8.7 HIGH · 🧪 PoC

## Beschreibung

frp is a fast reverse proxy. From 0.53.0 until 0.70.1, frp's optional SSH Tunnel Gateway in pkg/ssh/server.go parses an SSH exec channel request by adding 4 to an attacker-controlled four-byte big-endian length. A length of 0xFFFFFFFF makes the uint32 addition wrap to 3, defeats the payload bounds check, and causes payload[4:3] to panic in TunnelServer.handleNewChannel. When no authorized-keys file is configured, sshConfig.NoClientAuth permits an unauthenticated peer to reach this channel phase before the frp token is checked, so a single five-byte request terminates the frps process and drops every active tunnel. This issue is fixed in version 0.70.1.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
```

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

## Patch verfügbar (OSV)

- 7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b (Commit)
- fa3bcca2b0c4753cd4f0e2ab189dd6a5a6a15708 (Commit)

## Referenzen

- <https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp>
- <https://github.com/fatedier/frp/pull/5428>
- <https://github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b>
- <https://github.com/fatedier/frp/releases/tag/v0.70.1>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-73564) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_