{"api_version":"1","generated_at":"2026-10-08T08:02:57+00:00","cve":"CVE-2026-98215","urls":{"html":"https://cve.report/CVE-2026-98215","api":"https://cve.report/api/cve/CVE-2026-98215.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98215","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98215"},"summary":{"title":"selinux: preserve user SID across nested backing files","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: preserve user SID across nested backing files\n\nSELinux saves the user file SID in a backing-file security blob so it\nremains available after mmap() replaces vma->vm_file with a backing file.\n\nFor nested backing files (overlayfs over overlayfs, or FUSE passthrough\nbacked by overlayfs), user_file may itself be a backing file.  Its\nfsec->sid is the SID of the mounter that opened it, rather than the user\nthat opened the top-level file.  mprotect() then checks fd { use } against\nthe mounter SID.  This can incorrectly deny access without a domain\ntransition, or check the wrong target SID after one.\n\nCopy the saved user SID when user_file is a backing file.  Keep using the\nregular file SID for the first backing layer.\n\nWith two nested overlayfs mounts and SELinux enforcing,\nmprotect(PROT_READ) returns EACCES with an fd { use } denial against the\nmounter SID.  With this change, mprotect() succeeds.\n\nTested on arm64 QEMU with a small BusyBox initramfs and a purpose-built\nSELinux policy.  The original test was also repeated with Fedora Cloud\nBase 44 userspace and gave the same result.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-06 09:18:08","updated_at":"2026-10-06 09:18:08"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/8c0c602202b9a4909b00bc3354e3c0355bc69e65","name":"https://git.kernel.org/stable/c/8c0c602202b9a4909b00bc3354e3c0355bc69e65","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9d99b770e7b67b00bdef9005b928aad13e1d679b","name":"https://git.kernel.org/stable/c/9d99b770e7b67b00bdef9005b928aad13e1d679b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ff20d16b2e8230c034e21540043df47222dcc09b","name":"https://git.kernel.org/stable/c/ff20d16b2e8230c034e21540043df47222dcc09b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6aaeec59aadcd1eafc18b049f1b759fb6b9d9569","name":"https://git.kernel.org/stable/c/6aaeec59aadcd1eafc18b049f1b759fb6b9d9569","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/caa1b913d90d5dc07073733326d2af0f0288f089","name":"https://git.kernel.org/stable/c/caa1b913d90d5dc07073733326d2af0f0288f089","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98215","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected bc6c380c1159de52a252ed11f19a42c47f60a735 caa1b913d90d5dc07073733326d2af0f0288f089 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8bacd09f12c27710228562e4d13163e58c5f4a45 6aaeec59aadcd1eafc18b049f1b759fb6b9d9569 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d844702198395d3f80222777030f69db6be6b709 9d99b770e7b67b00bdef9005b928aad13e1d679b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 82544d36b1729153c8aeb179e84750f0c085d3b1 ff20d16b2e8230c034e21540043df47222dcc09b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 82544d36b1729153c8aeb179e84750f0c085d3b1 8c0c602202b9a4909b00bc3354e3c0355bc69e65 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cd0e707a927a70cdfd8bc5a512a9719a87f5ed51 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.144 6.6.158 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.95 6.12.112 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18.38 6.18.54 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.0.4 7.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.1","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.158 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.112 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.54 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.8 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc4 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"98215","cve":"CVE-2026-98215","epss":"0.002090000","percentile":"0.100660000","score_date":"2026-10-06","updated_at":"2026-10-07 00:14:55"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["security/selinux/hooks.c","security/selinux/include/objsec.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"caa1b913d90d5dc07073733326d2af0f0288f089","status":"affected","version":"bc6c380c1159de52a252ed11f19a42c47f60a735","versionType":"git"},{"lessThan":"6aaeec59aadcd1eafc18b049f1b759fb6b9d9569","status":"affected","version":"8bacd09f12c27710228562e4d13163e58c5f4a45","versionType":"git"},{"lessThan":"9d99b770e7b67b00bdef9005b928aad13e1d679b","status":"affected","version":"d844702198395d3f80222777030f69db6be6b709","versionType":"git"},{"lessThan":"ff20d16b2e8230c034e21540043df47222dcc09b","status":"affected","version":"82544d36b1729153c8aeb179e84750f0c085d3b1","versionType":"git"},{"lessThan":"8c0c602202b9a4909b00bc3354e3c0355bc69e65","status":"affected","version":"82544d36b1729153c8aeb179e84750f0c085d3b1","versionType":"git"},{"status":"affected","version":"cd0e707a927a70cdfd8bc5a512a9719a87f5ed51","versionType":"git"},{"lessThan":"6.6.158","status":"affected","version":"6.6.144","versionType":"semver"},{"lessThan":"6.12.112","status":"affected","version":"6.12.95","versionType":"semver"},{"lessThan":"6.18.54","status":"affected","version":"6.18.38","versionType":"semver"},{"lessThan":"7.1","status":"affected","version":"7.0.4","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["security/selinux/hooks.c","security/selinux/include/objsec.h"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"7.1"},{"lessThan":"7.1","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.158","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.112","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.54","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.8","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc4","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.158","versionStartIncluding":"6.6.144","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.112","versionStartIncluding":"6.12.95","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.54","versionStartIncluding":"6.18.38","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.8","versionStartIncluding":"7.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc4","versionStartIncluding":"7.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.4","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: preserve user SID across nested backing files\n\nSELinux saves the user file SID in a backing-file security blob so it\nremains available after mmap() replaces vma->vm_file with a backing file.\n\nFor nested backing files (overlayfs over overlayfs, or FUSE passthrough\nbacked by overlayfs), user_file may itself be a backing file.  Its\nfsec->sid is the SID of the mounter that opened it, rather than the user\nthat opened the top-level file.  mprotect() then checks fd { use } against\nthe mounter SID.  This can incorrectly deny access without a domain\ntransition, or check the wrong target SID after one.\n\nCopy the saved user SID when user_file is a backing file.  Keep using the\nregular file SID for the first backing layer.\n\nWith two nested overlayfs mounts and SELinux enforcing,\nmprotect(PROT_READ) returns EACCES with an fd { use } denial against the\nmounter SID.  With this change, mprotect() succeeds.\n\nTested on arm64 QEMU with a small BusyBox initramfs and a purpose-built\nSELinux policy.  The original test was also repeated with Fedora Cloud\nBase 44 userspace and gave the same result."}],"providerMetadata":{"dateUpdated":"2026-10-06T08:44:51.412Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/caa1b913d90d5dc07073733326d2af0f0288f089"},{"url":"https://git.kernel.org/stable/c/6aaeec59aadcd1eafc18b049f1b759fb6b9d9569"},{"url":"https://git.kernel.org/stable/c/9d99b770e7b67b00bdef9005b928aad13e1d679b"},{"url":"https://git.kernel.org/stable/c/ff20d16b2e8230c034e21540043df47222dcc09b"},{"url":"https://git.kernel.org/stable/c/8c0c602202b9a4909b00bc3354e3c0355bc69e65"}],"title":"selinux: preserve user SID across nested backing files","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98215","datePublished":"2026-10-06T08:44:51.412Z","dateReserved":"2026-09-25T10:25:14.326Z","dateUpdated":"2026-10-06T08:44:51.412Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-06 09:18:08","lastModifiedDate":"2026-10-06 09:18:08","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98215","Ordinal":"1","Title":"selinux: preserve user SID across nested backing files","CVE":"CVE-2026-98215","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98215","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: preserve user SID across nested backing files\n\nSELinux saves the user file SID in a backing-file security blob so it\nremains available after mmap() replaces vma->vm_file with a backing file.\n\nFor nested backing files (overlayfs over overlayfs, or FUSE passthrough\nbacked by overlayfs), user_file may itself be a backing file.  Its\nfsec->sid is the SID of the mounter that opened it, rather than the user\nthat opened the top-level file.  mprotect() then checks fd { use } against\nthe mounter SID.  This can incorrectly deny access without a domain\ntransition, or check the wrong target SID after one.\n\nCopy the saved user SID when user_file is a backing file.  Keep using the\nregular file SID for the first backing layer.\n\nWith two nested overlayfs mounts and SELinux enforcing,\nmprotect(PROT_READ) returns EACCES with an fd { use } denial against the\nmounter SID.  With this change, mprotect() succeeds.\n\nTested on arm64 QEMU with a small BusyBox initramfs and a purpose-built\nSELinux policy.  The original test was also repeated with Fedora Cloud\nBase 44 userspace and gave the same result.","Type":"Description","Title":"selinux: preserve user SID across nested backing files"}]}}}