CVE-2021-3493

{"id": "CVE-2021-3493", "cveTags": [], "metrics": {"cvssMetricV2": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"version": "2.0", "baseScore": 7.2, "accessVector": "LOCAL", "vectorString": "AV:L/AC:L/Au:N/C:C/I:C/A:C", "authentication": "NONE", "integrityImpact": "COMPLETE", "accessComplexity": "LOW", "availabilityImpact": "COMPLETE", "confidentialityImpact": "COMPLETE"}, "acInsufInfo": false, "impactScore": 10.0, "baseSeverity": "HIGH", "obtainAllPrivilege": false, "exploitabilityScore": 3.9, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}], "cvssMetricV31": [{"type": "Secondary", "source": "security@ubuntu.com", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 8.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 6.0, "exploitabilityScore": 2.0}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.8}]}, "published": "2021-04-17T05:15:14.630", "references": [{"url": "http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html", "tags": ["Exploit", "Third Party Advisory", "VDB Entry"], "source": "security@ubuntu.com"}, {"url": "http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html", "tags": ["Third Party Advisory", "VDB Entry"], "source": "security@ubuntu.com"}, {"url": "http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html", "tags": ["Exploit", "Third Party Advisory", "VDB Entry"], "source": "security@ubuntu.com"}, {"url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52", "tags": ["Mailing List", "Patch", "Third Party Advisory"], "source": "security@ubuntu.com"}, {"url": "https://ubuntu.com/security/notices/USN-4917-1", "tags": ["Vendor Advisory"], "source": "security@ubuntu.com"}, {"url": "https://www.openwall.com/lists/oss-security/2021/04/16/1", "tags": ["Mailing List", "Third Party Advisory"], "source": "security@ubuntu.com"}, {"url": "http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html", "tags": ["Exploit", "Third Party Advisory", "VDB Entry"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html", "tags": ["Third Party Advisory", "VDB Entry"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html", "tags": ["Exploit", "Third Party Advisory", "VDB Entry"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52", "tags": ["Mailing List", "Patch", "Third Party Advisory"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://ubuntu.com/security/notices/USN-4917-1", "tags": ["Vendor Advisory"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://www.openwall.com/lists/oss-security/2021/04/16/1", "tags": ["Mailing List", "Third Party Advisory"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "security@ubuntu.com", "description": [{"lang": "en", "value": "CWE-270"}]}, {"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-863"}]}], "descriptions": [{"lang": "en", "value": "The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges."}, {"lang": "es", "value": "La implementaci\u00f3n de overlayfs en el kernel de Linux no comprob\u00f3 apropiadamente con respecto a los espacios de nombre de los usuarios, la configuraci\u00f3n de las capacidades de los archivos en un sistema de archivos subyacente. Debido a la combinaci\u00f3n de los espacios de nombre de usuarios no privilegiados junto con un parche incluido en el kernel de Ubuntu para permitir montajes de superposici\u00f3n no privilegiados, un atacante podr\u00eda usar esto para alcanzar privilegios elevados"}], "lastModified": "2025-10-22T00:17:44.043", "cisaActionDue": "2022-11-10", "cisaExploitAdd": "2022-10-20", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*", "vulnerable": true, "matchCriteriaId": "90A80DE7-3EFA-464C-9D31-C46521FFBFBF", "versionEndExcluding": "18.04"}, {"criteria": "cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:lts:*:*:*", "vulnerable": true, "matchCriteriaId": "2027773B-26DA-408E-B71D-40D05690D9EA", "versionEndExcluding": "20.04", "versionStartIncluding": "18.04.1"}], "operator": "OR"}]}, {"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:canonical:ubuntu_linux:*:*:*:*:-:*:*:*", "vulnerable": true, "matchCriteriaId": "ACAB2EE0-EC21-4669-840F-94F6C3028C64", "versionEndExcluding": "20.10"}], "operator": "OR"}]}], "sourceIdentifier": "security@ubuntu.com", "cisaRequiredAction": "Apply updates per vendor instructions.", "cisaVulnerabilityName": "Linux Kernel Privilege Escalation Vulnerability"}