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VulnerabilityPublished 07/24/2026

frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow

Affects github.com/fatedier/frpSource GCVE Database

0

Fixed in 0.70.1 : patch github.com/fatedier/frp soon.

Data as of 07/25/2026, 23:52:21 UTC

Severity
High

Rated by Threat Radar

Patch
Available – fixed in 0.70.1
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

What to do

Affected software

ProductAffectedFixed in
Gogithub.com/fatedier/frpAffected
  • >=0.53.0 <0.70.1
Fixed in
  • 0.70.1

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AI-suggested

Do not enable the SSH Tunnel Gateway or configure it with an authorized-keys file to require client authentication. Disabling the SSH Tunnel Gateway or enabling client authentication prevents unauthenticated access to the vulnerable code path.

Description

An integer overflow vulnerability in the frp server's SSH Tunnel Gateway allows an unauthenticated remote attacker to crash the entire frps process by sending a specially crafted five-byte message. This causes a slice bounds out-of-range panic in the Go runtime, terminating the server process and dropping all active tunnels. The vulnerability is reachable without authentication when the SSH Tunnel Gateway is enabled with no authorized-keys file, which is the default mode. There is no confidentiality or code execution impact. The issue affects frp versions from v0.53.0 through v0.70.0 with the SSH Tunnel Gateway enabled.

Impact

An unauthenticated remote attacker can cause a denial of service by crashing the frps server process with a single crafted message, resulting in all active tunnels being dropped and new connections refused until the server is restarted. The crash is trivially repeatable, enabling sustained outages. There is no impact on confidentiality, integrity, or code execution. Only frps instances with the SSH Tunnel Gateway explicitly enabled and configured without client authentication are affected.

Weaknesses

References

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