frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow
Affects github.com/fatedier/frpSource GCVE Database
Fixed in 0.70.1 : patch github.com/fatedier/frp soon.
Data as of 07/25/2026, 23:52:21 UTC
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:NWhat to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Gogithub.com/fatedier/frp | Affected
| Fixed in
|
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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
- CWE-129Improper Validation of Array Index (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.
- CWE-190Integer Overflow or Wraparound (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
References
- github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp (opens in a new tab)
- github.com/fatedier/frp/pull/5428 (opens in a new tab)
- github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b (opens in a new tab)
- github.com/fatedier/frp (opens in a new tab)
- github.com/fatedier/frp/releases/tag/v0.70.1 (opens in a new tab)