{"id":"CVE-2026-73564","state":"PUBLISHED","title":"frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow","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.","publishedAt":"2026-08-13T17:35:46.762Z","updatedAt":"2026-08-13T17:53:06.534Z","severity":{"score":8.7,"label":"High","version":"4.0","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","source":"GitHub_M"},"assigner":"GitHub_M","products":["fatedier frp"],"affected":[{"vendor":"fatedier","product":"frp","versions":[{"version":">= 0.53.0, < 0.70.1","status":"affected"}]}],"references":["https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp","https://github.com/fatedier/frp/pull/5428","https://github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b","https://github.com/fatedier/frp/releases/tag/v0.70.1"],"weaknesses":["CWE-129","CWE-190"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/73xxx/CVE-2026-73564.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-73564","state":"PUBLISHED","datePublished":"2026-08-13T17:35:46.762Z","dateUpdated":"2026-08-13T17:53:06.534Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-08-12T20:53:46.380Z"},"containers":{"cna":{"title":"frp: Unauthenticated Remote Denial of Service in the frp SSH Tunnel Gateway via Integer Overflow","descriptions":[{"lang":"en","value":"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":[{"vendor":"fatedier","product":"frp","versions":[{"version":">= 0.53.0, < 0.70.1","status":"affected"}]}],"references":[{"url":"https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp","name":"https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/fatedier/frp/pull/5428","name":"https://github.com/fatedier/frp/pull/5428","tags":["x_refsource_MISC"]},{"url":"https://github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b","name":"https://github.com/fatedier/frp/commit/7dc7be930e2452ae93fd32f2a77f8c6fcd0b652b","tags":["x_refsource_MISC"]},{"url":"https://github.com/fatedier/frp/releases/tag/v0.70.1","name":"https://github.com/fatedier/frp/releases/tag/v0.70.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.7,"baseSeverity":"HIGH","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-129","lang":"en","description":"CWE-129: Improper Validation of Array Index","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-190","lang":"en","description":"CWE-190: Integer Overflow or Wraparound","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-13T17:35:46.762Z"},"source":{"advisory":"GHSA-26gq-p25f-99cp","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/fatedier/frp/security/advisories/GHSA-26gq-p25f-99cp","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-13T17:52:30.634352Z","id":"CVE-2026-73564","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-13T17:53:06.534Z"}}]}}}