Vulnerability · Published Aug 13, 2026 · Assigned by GitHub_M

CVE-2026-73564frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow

High 8.7

In plain English

A high-severity integer overflow in frp from fatedier. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.5%top 55.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/fatedier/frp	0.70.1	GHSA-26gq-p25f-99cp
Go	github.com/fatedier/frp	0.70.1	GO-2026-6103

Affected products (as reported)

Vendor	Product	Versions
fatedier	frp	>= 0.53.0, < 0.70.1

Weakness: CWE-129, CWE-190 · Vector: 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

References

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