{"id":"CVE-2026-53791","state":"PUBLISHED","title":"rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header","description":"rsync daemon before 3.5.0 contains an IP address spoofing vulnerability that allows unauthenticated remote attackers to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source address. Attackers who can connect directly to the rsync daemon can inject a spoofed source IP in the PROXY protocol header to circumvent hosts allow/deny rules, gaining unauthorized access that would otherwise be blocked based on their real source address.","publishedAt":"2026-08-13T14:38:10.300Z","updatedAt":"2026-08-14T18:09:56.975Z","severity":{"score":9.1,"label":"Critical","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["RsyncProject rsync"],"affected":[{"vendor":"RsyncProject","product":"rsync","packageURL":"pkg:github/RsyncProject/rsync","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"3.4.4","versionType":"semver"},{"version":"3.5.0","status":"unaffected","versionType":"semver"}],"repo":"https://github.com/RsyncProject/rsync"}],"references":["https://github.com/RsyncProject/rsync/security/advisories/GHSA-h2q9-5fr8-w635","https://github.com/RsyncProject/rsync/releases/tag/v3.5.0","https://www.vulncheck.com/advisories/rsync-daemon-ip-spoofing-via-proxy-protocol-header"],"weaknesses":["CWE-290"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53791.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53791","state":"PUBLISHED","datePublished":"2026-08-13T14:38:10.300Z","dateUpdated":"2026-08-14T18:09:56.975Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-06-10T20:14:32.827Z"},"containers":{"cna":{"title":"rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header","descriptions":[{"lang":"en","value":"rsync daemon before 3.5.0 contains an IP address spoofing vulnerability that allows unauthenticated remote attackers to bypass IP-based access controls by sending a crafted PROXY protocol header with a forged source address. Attackers who can connect directly to the rsync daemon can inject a spoofed source IP in the PROXY protocol header to circumvent hosts allow/deny rules, gaining unauthorized access that would otherwise be blocked based on their real source address."}],"affected":[{"vendor":"RsyncProject","product":"rsync","packageURL":"pkg:github/RsyncProject/rsync","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"3.4.4","versionType":"semver"},{"version":"3.5.0","status":"unaffected","versionType":"semver"}],"repo":"https://github.com/RsyncProject/rsync"}],"references":[{"url":"https://github.com/RsyncProject/rsync/security/advisories/GHSA-h2q9-5fr8-w635","name":"GitHub Security Advisory (GHSA-h2q9-5fr8-w635)","tags":["vendor-advisory"]},{"url":"https://github.com/RsyncProject/rsync/releases/tag/v3.5.0","name":"rsync 3.5.0 Release Notes","tags":["release-notes"]},{"url":"https://www.vulncheck.com/advisories/rsync-daemon-ip-spoofing-via-proxy-protocol-header","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"CRITICAL","baseScore":9.1,"vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"}},{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE","baseSeverity":"CRITICAL","baseScore":9.1,"vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-290","lang":"en","description":"CWE-290 Authentication Bypass by Spoofing","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-08-14T16:50:09.199Z"},"datePublic":"2026-08-12T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:*","versionEndIncluding":"3.4.4"}]}]}],"source":{"discovery":"INTERNAL"},"x_generator":{"engine":"Vulnogram 1.0.4"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-14T18:02:57.002288Z","id":"CVE-2026-53791","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-14T18:09:56.975Z"}}]}}}