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.
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-26gq-p25f-99cp | frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 13 Aug 2026 18:45:00 +0000
| Type | Values Removed | Values Added |
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| First Time appeared |
Fatedier
Fatedier frp |
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| Vendors & Products |
Fatedier
Fatedier frp |
Thu, 13 Aug 2026 17:45:00 +0000
| Type | Values Removed | Values Added |
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| 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. | |
| Title | frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow | |
| Weaknesses | CWE-129 CWE-190 |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-08-13T17:53:06.534Z
Reserved: 2026-08-12T20:53:46.380Z
Link: CVE-2026-73564
No data.
Status : Received
Published: 2026-08-13T18:18:18.950
Modified: 2026-08-13T18:18:18.950
Link: CVE-2026-73564
No data.
OpenCVE Enrichment
Updated: 2026-08-13T18:45:04Z
Github GHSA