{"id":"CVE-2026-73564","aliases":["GHSA-26gq-p25f-99cp"],"url":"https://o3.security/vulnerability/CVE-2026-73564","summary":"frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow","details":"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.","published":"2026-08-13T17:35:46.762Z","modified":"2026-08-14T04:04:07.260333903Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Go","name":"github.com/fatedier/frp","fixedVersion":"0.70.1"}],"fix":{"url":"https://github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b","label":"fatedier/frp@7dc7be9"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73564.json"},{"type":"FIX","url":"https://github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b"},{"type":"FIX","url":"https://github.com/fatedier/frp/pull/5428"},{"type":"WEB","url":"https://github.com/fatedier/frp/releases/tag/v0.70.1"},{"type":"ADVISORY","url":"https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73564"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-14T04:04:07.260333903Z"}}