{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-70455", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-08-04T14:52:23.814Z", "datePublished": "2026-08-13T14:45:11.164Z", "dateUpdated": "2026-08-14T16:51:20.314Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-08-14T16:51:20.314Z"}, "title": "rsync 3.4.2 < 3.5.0 DoS via --zt Zstandard Compression Thread Exhaustion", "datePublic": "2026-08-12T00:00:00.000Z", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-770", "description": "CWE-770 Allocation of Resources Without Limits or Throttling", "type": "CWE"}]}], "affected": [{"vendor": "RsyncProject", "product": "rsync", "repo": "https://github.com/RsyncProject/rsync", "versions": [{"status": "affected", "version": "3.4.2", "lessThanOrEqual": "3.4.4", "versionType": "semver"}, {"status": "unaffected", "version": "3.5.0", "versionType": "semver"}], "defaultStatus": "unaffected", "packageURL": "pkg:github/RsyncProject/rsync"}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.4.2", "versionEndIncluding": "3.4.4"}]}]}], "descriptions": [{"lang": "en", "value": "rsync 3.4.2 before 3.5.0\u00a0contains a denial of service vulnerability that allows a remote sender to exhaust system resources by specifying the --zt short alias for --compress-threads, which bypasses the refuse options directive's string matching on long option names. Attackers can specify --zt=N with a large value to spawn an unbounded number of Zstandard worker threads on the receiver, exhausting available thread and memory resources.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>rsync 3.4.2 before 3.5.0&nbsp;contains a denial of service vulnerability that allows a remote sender to exhaust system resources by specifying the --zt short alias for --compress-threads, which bypasses the refuse options directive's string matching on long option names. Attackers can specify --zt=N with a large value to spawn an unbounded number of Zstandard worker threads on the receiver, exhausting available thread and memory resources.</p>"}]}], "references": [{"url": "https://github.com/RsyncProject/rsync/security/advisories/GHSA-rjvj-qgqg-cvx9", "name": "GitHub Security Advisory (GHSA-rjvj-qgqg-cvx9)", "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-dos-via-zt-zstandard-compression-thread-exhaustion", "tags": ["third-party-advisory"]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "Remote sender specifies --zt=N (Zstandard short alias not covered by refuse options) to spawn unbounded worker threads on the receiver (VA:H)."}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "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": "HIGH", "baseScore": 8.7, "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"}}, {"format": "CVSS", "scenarios": [{"lang": "en", "value": "CVSS 3.1 reference score."}], "cvssV3_1": {"version": "3.1", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH", "baseSeverity": "HIGH", "baseScore": 7.5, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}}], "credits": [{"lang": "en", "value": "fcasal", "type": "finder"}], "source": {"discovery": "EXTERNAL"}, "x_generator": {"engine": "Vulnogram 1.0.4"}}}}

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{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.4.2,3.4.4]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "3.5.0"}}], "enrichment": {"confidence": 97.0, "confidence_source": "matching", "scores": [{"score": 97.0, "source": "matching"}]}, "original": {"product": "rsync", "source": "cna", "vendor": "RsyncProject"}, "product": "rsync", "vendor": "rsync_project"}], "created": "2026-08-13T17:15:05.159617+00:00", "updated": "2026-08-14T10:00:03.922073+00:00", "vendors": ["rsync_project", "rsync_project$PRODUCT$rsync"]}