CVE-2026-29518

Rsync versions before 3.4.3 contain a time-of-check to time-of-use (TOCTOU) race condition in daemon file handling that allows attackers to redirect file writes outside intended directories by replacing parent directory components with symbolic links. Attackers with write access to a module path can exploit this race condition to create or overwrite arbitrary files, potentially modifying sensitive system files and achieving privilege escalation when the daemon runs with elevated privileges. This vulnerability can only be triggered if the chroot setting is false.

CVSS v3 7.0 HIGH

7.0^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.0 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/RsyncProject/rsync/pull/895/changes/8471fdd1561049ef5f58df44a1811a50bd9a531d	Patch
https://github.com/RsyncProject/rsync/releases/tag/v3.4.3	Release Notes
https://michael.stapelberg.ch/posts/2026-05-24-minimal-memory-safe-go-rsync-vulns/
https://www.vulncheck.com/advisories/rsync-toctou-race-condition-allows-symlink-based-arbitrary-file-write	Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:26332
https://access.redhat.com/errata/RHSA-2026:26408
https://access.redhat.com/errata/RHSA-2026:26410
https://access.redhat.com/errata/RHSA-2026:29197
https://access.redhat.com/errata/RHSA-2026:54769
https://access.redhat.com/security/cve/CVE-2026-29518
https://bugzilla.redhat.com/show_bug.cgi?id=2469055
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29518.json

Configurations

Configuration 1 (hide)

cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-05-20 13:16

Updated : 2026-08-19 12:17

NVD link : CVE-2026-29518

Mitre link : CVE-2026-29518

CVE.ORG link : CVE-2026-29518

JSON object : View

Products Affected

samba

rsync

CWE

CWE-367

Time-of-check Time-of-use (TOCTOU) Race Condition

{"id": "CVE-2026-29518", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-29518", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-05-20T14:50:13.900176Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.0, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.0}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 6.0, "exploitabilityScore": 1.1}], "cvssMetricV40": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 7.3, "Automatable": "NOT_DEFINED", "attackVector": "LOCAL", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "LOW", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "disclosure@vulncheck.com", "affectedData": [{"repo": "https://github.com/RsyncProject/rsync", "vendor": "RsyncProject", "product": "rsync", "versions": [{"status": "affected", "version": "0", "lessThan": "3.4.3", "versionType": "semver"}], "packageURL": "pkg:github/RsyncProject/rsync", "defaultStatus": "unaffected"}]}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "affectedData": [{"cpes": ["cpe:/o:redhat:enterprise_linux:10.2"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "versions": [{"status": "unaffected", "version": "0:3.4.4-1.el10_2", "lessThan": "*", "versionType": "rpm"}], "packageName": "rsync", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:8"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "versions": [{"status": "unaffected", "version": "0:3.1.3-27.el8_10", "lessThan": "*", "versionType": "rpm"}], "packageName": "rsync", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:enterprise_linux:9", "cpe:/o:redhat:enterprise_linux:9"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "versions": [{"status": "unaffected", "version": "0:3.2.5-7.el9_8.2", "lessThan": "*", "versionType": "rpm"}], "packageName": "rsync", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:openshift:4.22::el9"], "vendor": "Red Hat", "product": "Red Hat OpenShift Container Platform 4.22", "versions": [{"status": "unaffected", "version": "4.22.9.8.202608130832-0", "lessThan": "*", "versionType": "rpm"}], "packageName": "rhcos", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:discovery:2::el9"], "vendor": "Red Hat", "product": "Red Hat Discovery 2", "versions": [{"status": "unaffected", "version": "1782166952", "lessThan": "*", "versionType": "rpm"}], "packageName": "discovery/discovery-ui-rhel9", "collectionURL": "https://catalog.redhat.com/software/containers/", "defaultStatus": "affected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:6"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "packageName": "rsync", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:7"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "packageName": "rsync", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}]}], "published": "2026-05-20T13:16:17.040", "references": [{"url": "https://github.com/RsyncProject/rsync/pull/895/changes/8471fdd1561049ef5f58df44a1811a50bd9a531d", "tags": ["Patch"], "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/RsyncProject/rsync/releases/tag/v3.4.3", "tags": ["Release Notes"], "source": "disclosure@vulncheck.com"}, {"url": "https://michael.stapelberg.ch/posts/2026-05-24-minimal-memory-safe-go-rsync-vulns/", "source": "disclosure@vulncheck.com"}, {"url": "https://www.vulncheck.com/advisories/rsync-toctou-race-condition-allows-symlink-based-arbitrary-file-write", "tags": ["Third Party Advisory"], "source": "disclosure@vulncheck.com"}, {"url": "https://access.redhat.com/errata/RHSA-2026:26332", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/errata/RHSA-2026:26408", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/errata/RHSA-2026:26410", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/errata/RHSA-2026:29197", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/errata/RHSA-2026:54769", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-29518", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2469055", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29518.json", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "description": [{"lang": "en", "value": "CWE-367"}]}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "description": [{"lang": "en", "value": "CWE-367"}]}], "descriptions": [{"lang": "en", "value": "Rsync versions before 3.4.3 contain a time-of-check to time-of-use (TOCTOU) race condition in daemon file handling that allows attackers to redirect file writes outside intended directories by replacing parent directory components with symbolic links. Attackers with write access to a module path can exploit this race condition to create or overwrite arbitrary files, potentially modifying sensitive system files and achieving privilege escalation when the daemon runs with elevated privileges. This vulnerability can only be triggered if the chroot setting is false."}, {"lang": "es", "value": "Las versiones de Rsync anteriores a la 3.4.3 contienen una condici\u00f3n de carrera de tiempo de verificaci\u00f3n a tiempo de uso (TOCTOU) en el manejo de archivos del demonio que permite a los atacantes redirigir escrituras de archivos fuera de los directorios previstos reemplazando componentes de directorios padre con enlaces simb\u00f3licos. Los atacantes con acceso de escritura a una ruta de m\u00f3dulo pueden explotar esta condici\u00f3n de carrera para crear o sobrescribir archivos arbitrarios, modificando potencialmente archivos sensibles del sistema y logrando la escalada de privilegios cuando el demonio se ejecuta con privilegios elevados. Esta vulnerabilidad solo puede activarse si la configuraci\u00f3n de chroot es falsa."}], "lastModified": "2026-08-19T12:17:41.960", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:samba:rsync:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "BBA148E3-868F-4A1F-AAD0-16FE15A265DC", "versionEndExcluding": "3.4.3"}], "operator": "OR"}]}], "sourceIdentifier": "disclosure@vulncheck.com"}