CVE-2026-76642

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-76642", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-08-19T14:53:58.575Z", "datePublished": "2026-09-03T10:54:08.150Z", "dateUpdated": "2026-09-03T14:00:29.374Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-09-03T10:54:08.150Z"}, "datePublic": "2026-09-02T00:00:00.000Z", "title": "util-linux libmount Privilege Escalation via Failed Mount Helper", "descriptions": [{"lang": "en", "value": "util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with inherited suid bits or modify target inode permissions after a helper fails, achieving privilege escalation."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Detection of Error Condition Without Action", "cweId": "CWE-390", "type": "CWE"}]}], "affected": [{"vendor": "util-linux", "product": "util-linux", "defaultStatus": "unaffected", "packageURL": "pkg:github/util-linux/util-linux", "versions": [{"version": "2.39", "lessThan": "2.41.6", "status": "affected", "versionType": "custom"}, {"version": "2.42", "lessThan": "2.42.3", "status": "affected", "versionType": "custom"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.39", "versionEndExcluding": "2.41.6"}, {"vulnerable": true, "criteria": "cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.42", "versionEndExcluding": "2.42.3"}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 8.5, "baseSeverity": "HIGH"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH"}}], "references": [{"url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f", "name": "GitHub Security Advisory (GHSA-m25x-3hj9-m26f)", "tags": ["vendor-advisory"]}, {"url": "https://github.com/util-linux/util-linux/commit/f57cea130839c0af8dc0525274267ae4cfd66bbf", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://github.com/util-linux/util-linux/commit/1d14676ea70003e9f5b2a6a76af0cadb1190411a", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://github.com/util-linux/util-linux/commit/a15c00a9e545aa8b9cf6ec0f888ff6c7b3eaeedc", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476", "tags": ["technical-description"]}, {"url": "https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892", "tags": ["technical-description"]}, {"url": "https://github.com/util-linux/util-linux", "tags": ["product"]}, {"name": "VulnCheck Advisory: util-linux libmount Privilege Escalation via Failed Mount Helper", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/util-linux-libmount-privilege-escalation-via-failed-mount-helper"}], "credits": [{"lang": "en", "value": "Andreas Gabriel Berbescu", "type": "reporter"}, {"lang": "en", "value": "Ivan Redondo Plaza", "type": "reporter"}], "x_generator": {"engine": "vulncheck-endgame"}}, "adp": [{"references": [{"url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-09-03T14:00:22.814411Z", "id": "CVE-2026-76642", "options": [{"Exploitation": "poc"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-03T14:00:29.374Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-76642", "role": "CISA Coordinator", "options": [{"Exploitation": "poc"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-09-03T14:00:22.814411Z"}}}], "references": [{"url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f", "tags": ["exploit"]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-03T14:00:05.019Z"}}], "cna": {"title": "util-linux libmount Privilege Escalation via Failed Mount Helper", "credits": [{"lang": "en", "type": "reporter", "value": "Andreas Gabriel Berbescu"}, {"lang": "en", "type": "reporter", "value": "Ivan Redondo Plaza"}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "baseScore": 8.5, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH"}}, {"format": "CVSS", "cvssV3_1": {"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"}}], "affected": [{"vendor": "util-linux", "product": "util-linux", "versions": [{"status": "affected", "version": "2.39", "lessThan": "2.41.6", "versionType": "custom"}, {"status": "affected", "version": "2.42", "lessThan": "2.42.3", "versionType": "custom"}], "packageURL": "pkg:github/util-linux/util-linux", "defaultStatus": "unaffected"}], "datePublic": "2026-09-02T00:00:00.000Z", "references": [{"url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f", "name": "GitHub Security Advisory (GHSA-m25x-3hj9-m26f)", "tags": ["vendor-advisory"]}, {"url": "https://github.com/util-linux/util-linux/commit/f57cea130839c0af8dc0525274267ae4cfd66bbf", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://github.com/util-linux/util-linux/commit/1d14676ea70003e9f5b2a6a76af0cadb1190411a", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://github.com/util-linux/util-linux/commit/a15c00a9e545aa8b9cf6ec0f888ff6c7b3eaeedc", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476", "tags": ["technical-description"]}, {"url": "https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892", "tags": ["technical-description"]}, {"url": "https://github.com/util-linux/util-linux", "tags": ["product"]}, {"url": "https://www.vulncheck.com/advisories/util-linux-libmount-privilege-escalation-via-failed-mount-helper", "name": "VulnCheck Advisory: util-linux libmount Privilege Escalation via Failed Mount Helper", "tags": ["third-party-advisory"]}], "x_generator": {"engine": "vulncheck-endgame"}, "descriptions": [{"lang": "en", "value": "util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with inherited suid bits or modify target inode permissions after a helper fails, achieving privilege escalation."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-390", "description": "Detection of Error Condition Without Action"}]}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "2.41.6", "versionStartIncluding": "2.39"}, {"criteria": "cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "2.42.3", "versionStartIncluding": "2.42"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-09-03T10:54:08.150Z"}}}, "cveMetadata": {"cveId": "CVE-2026-76642", "state": "PUBLISHED", "dateUpdated": "2026-09-03T14:00:29.374Z", "dateReserved": "2026-08-19T14:53:58.575Z", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "datePublished": "2026-09-03T10:54:08.150Z", "assignerShortName": "VulnCheck"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "packageURL": "pkg:github/util-linux/util-linux", "product": "util-linux", "vendor": "util-linux", "versions": [{"lessThan": "2.41.6", "status": "affected", "version": "2.39", "versionType": "custom"}, {"lessThan": "2.42.3", "status": "affected", "version": "2.42", "versionType": "custom"}]}], "source": "disclosure@vulncheck.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "util-linux versions through 2.41.5 and 2.42.2 fail to check mount helper exit status before running post-mount hooks, allowing unprivileged users to execute privileged operations on pre-existing filesystems. Attackers can exploit X-mount.idmap or X-mount.owner hooks to clone filesystems with inherited suid bits or modify target inode permissions after a helper fails, achieving privilege escalation."}], "id": "CVE-2026-76642", "lastModified": "2026-09-24T20:28:01.780", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.5, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/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", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-76642", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-09-03T14:00:22.814411Z", "version": "2.0.3"}}]}, "published": "2026-09-03T13:06:08.440", "references": [{"source": "disclosure@vulncheck.com", "url": "https://github.com/util-linux/util-linux"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L476"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/util-linux/util-linux/blob/v2.42.2/libmount/src/context_mount.c#L892"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/util-linux/util-linux/commit/1d14676ea70003e9f5b2a6a76af0cadb1190411a"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/util-linux/util-linux/commit/a15c00a9e545aa8b9cf6ec0f888ff6c7b3eaeedc"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/util-linux/util-linux/commit/f57cea130839c0af8dc0525274267ae4cfd66bbf"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f"}, {"source": "disclosure@vulncheck.com", "url": "https://www.vulncheck.com/advisories/util-linux-libmount-privilege-escalation-via-failed-mount-helper"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-390"}], "source": "disclosure@vulncheck.com", "type": "Secondary"}]}

{"acknowledgement": "Red Hat would like to thank Andreas Gabriel Berbescu (Independent Security Researcher) and Iv\u00e1n Redondo Plaza (Independent Security Researcher) for reporting this issue.", "bugzilla": {"description": "util-linux: util-linux: failed external mount helper still runs privileged X-mount post-hooks", "id": "2521999", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2521999"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.8", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-390", "details": ["When an external mount.<type> helper runs but exits with a nonzero status, libmount still treats the helper invocation as successful and runs privileged post-mount hooks. A local unprivileged user with an /etc/fstab entry that uses the user option together with X-mount.idmap or X-mount.owner/group/mode can cause those hooks to clone or re-own the underlying filesystem after the helper fails, leading to local privilege escalation."], "mitigation": {"lang": "en:us", "value": "Upgrade to util-linux v2.41.6, v2.42.3, or later. Until a fix is applied, avoid combining the user (or users) fstab option with X-mount.idmap or X-mount.owner/group/mode on entries that invoke an external mount.<type> helper. Administrators can also remove or restrict user-mountable fstab entries that specify those X-mount.* options."}, "name": "CVE-2026-76642", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "util-linux", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "util-linux", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "util-linux", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "rhel8/flatpak-runtime", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "rhel8/flatpak-sdk", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "util-linux", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "util-linux", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-09-02T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-76642\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-76642\nhttps://github.com/util-linux/util-linux/security/advisories/GHSA-m25x-3hj9-m26f"], "statement": "Affected versions: util-linux v2.39 through v2.42.2. Fixed in v2.41.6 and v2.42.3.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.39,2.41.6)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.42,2.42.3)"}}], "enrichment": {"confidence": 86.0, "confidence_source": "matching", "scores": [{"score": 86.0, "source": "matching"}]}, "original": {"product": "util-linux", "source": "cna", "vendor": "util-linux"}, "product": "util-linux", "vendor": "linux"}], "created": "2026-09-03T13:15:04.683006+00:00", "updated": "2026-09-03T15:30:05.324306+00:00", "vendors": ["linux", "linux$PRODUCT$util-linux"]}