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.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 8.7NVD modified 2026-10-23 18:10
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 5
- https://github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b
- https://github.com/fatedier/frp/pull/5428
- https://github.com/fatedier/frp/releases/tag/v0.70.1
- https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp
- https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp