CVE-2026-43391

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-43391", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.007Z", "datePublished": "2026-05-08T14:21:36.012Z", "dateUpdated": "2026-09-07T15:44:55.215Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-07T15:44:55.215Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnsfs: tighten permission checks for handle opening\n\nEven privileged services should not necessarily be able to see other\nprivileged service's namespaces so they can't leak information to each\nother. Use may_see_all_namespaces() helper that centralizes this policy\nuntil the nstree adapts."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The vulnerable path is reached through the local open_by_handle_at(2) syscall using the nsfs root anchor, then handle_to_path() -> exportfs_decode_fh_raw() -> nsfs_fh_to_dentry(). It is not reachable via network packets or physical interaction.\nAC:L - There is no race or memory-layout dependency; once the attacker supplies a valid or discoverable nsfs handle/namespace id, the authorization bypass is deterministic. Namespace ids are exposed through nsfs/listing interfaces and are not cryptographic secrets.\nPR:L - The pre-fix check required CAP_SYS_ADMIN in the target namespace's owning user namespace, which can be satisfied by a user-namespace/container root in plausible deployments. This is privileged local access, but not necessarily real root in the initial namespace.\nUI:N - Exploitation is performed entirely by the attacking process via syscalls. No victim user action is required.\nS:C - The bug lets one namespace-confined privileged context obtain handles to another service's namespaces, crossing the namespace/sandbox visibility boundary that the fix restores. The impacted resources can be outside the attacker's intended namespace security domain.\nC:H - An unauthorized namespace fd exposes namespace metadata and can be used with setns paths to enter target mount, IPC, UTS, network, or related namespaces when the old capability gate is satisfied. In a severe deployment this can expose private service resources and secrets.\nI:H - After obtaining the namespace fd, the attacker can join target namespaces where existing capability checks allow it and modify namespace-scoped state such as mounts, IPC objects, hostnames, or service environment. This supports high integrity impact against the isolated service domain.\nA:H - The same unauthorized namespace access can be used to disrupt target namespace state, such as breaking mounts or other namespace-scoped resources needed by the victim service. In the highest reasonable scenario this can cause complete service availability loss."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nsfs.c"], "versions": [{"version": "5222470b2fbb3740f931f189db33dd1367b1ae75", "lessThan": "24ebaf6676ae4f74f4856eb645959b15e62bc1b4", "status": "affected", "versionType": "git"}, {"version": "5222470b2fbb3740f931f189db33dd1367b1ae75", "lessThan": "1797ee11451f1b2be69863a9f5bd43b948813fdf", "status": "affected", "versionType": "git"}, {"version": "5222470b2fbb3740f931f189db33dd1367b1ae75", "lessThan": "d2324a9317f00013facb0ba00b00440e19d2af5e", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nsfs.c"], "versions": [{"version": "6.18", "status": "affected"}, {"version": "0", "lessThan": "6.18", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19.9", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "6.19.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "7.0"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/24ebaf6676ae4f74f4856eb645959b15e62bc1b4"}, {"url": "https://git.kernel.org/stable/c/1797ee11451f1b2be69863a9f5bd43b948813fdf"}, {"url": "https://git.kernel.org/stable/c/d2324a9317f00013facb0ba00b00440e19d2af5e"}], "title": "nsfs: tighten permission checks for handle opening", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/nsfs.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "24ebaf6676ae4f74f4856eb645959b15e62bc1b4", "status": "affected", "version": "5222470b2fbb3740f931f189db33dd1367b1ae75", "versionType": "git"}, {"lessThan": "1797ee11451f1b2be69863a9f5bd43b948813fdf", "status": "affected", "version": "5222470b2fbb3740f931f189db33dd1367b1ae75", "versionType": "git"}, {"lessThan": "d2324a9317f00013facb0ba00b00440e19d2af5e", "status": "affected", "version": "5222470b2fbb3740f931f189db33dd1367b1ae75", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/nsfs.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.18"}, {"lessThan": "6.18", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "6.19.*", "status": "unaffected", "version": "6.19.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.0", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "57F58163-F061-4520-9C0F-15D72CC3A1C2", "versionEndExcluding": "6.19.9", "versionStartIncluding": "6.18", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnsfs: tighten permission checks for handle opening\n\nEven privileged services should not necessarily be able to see other\nprivileged service's namespaces so they can't leak information to each\nother. Use may_see_all_namespaces() helper that centralizes this policy\nuntil the nstree adapts."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnsfs: endurecer las comprobaciones de permisos para la apertura de identificadores\n\nIncluso los servicios privilegiados no deber\u00edan necesariamente poder ver los espacios de nombres de otros servicios privilegiados para que no puedan filtrar informaci\u00f3n entre s\u00ed. Usar el asistente may_see_all_namespaces() que centraliza esta pol\u00edtica hasta que nstree se adapte."}], "id": "CVE-2026-43391", "lastModified": "2026-11-11T20:10:00.273", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.0, "impactScore": 6.0, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-05-08T15:16:50.490", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/1797ee11451f1b2be69863a9f5bd43b948813fdf"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/24ebaf6676ae4f74f4856eb645959b15e62bc1b4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/d2324a9317f00013facb0ba00b00440e19d2af5e"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "NVD-CWE-noinfo"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: nsfs: tighten permission checks for handle opening", "id": "2468185", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2468185"}, "csaw": false, "cwe": "CWE-1220", "details": ["A flaw was found in the Linux kernel's nsfs component. This vulnerability allows privileged services to potentially view the namespaces of other privileged services, leading to information disclosure. This could enable unauthorized access to sensitive data or configurations between isolated services."], "name": "CVE-2026-43391", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-05-08T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-43391\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-43391\nhttps://lore.kernel.org/linux-cve-announce/2026050836-CVE-2026-43391-4889@gregkh/T"]}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5222470b2fbb3740f931f189db33dd1367b1ae75,1797ee11451f1b2be69863a9f5bd43b948813fdf)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[5222470b2fbb3740f931f189db33dd1367b1ae75,d2324a9317f00013facb0ba00b00440e19d2af5e)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.18"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.18)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.19.9,6.20.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.0,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-05-08T17:15:16.439126+00:00", "updated": "2026-05-26T16:45:06.391930+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}