{"schema":"threatline.record/2","record":{"id":"CVE-2026-98215","aliases":[],"summary":"selinux: preserve user SID across nested backing files","details":"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.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"bc6c380c1159de52a252ed11f19a42c47f60a735","lessThan":"caa1b913d90d5dc07073733326d2af0f0288f089","status":"affected","versionType":"git"},{"version":"8bacd09f12c27710228562e4d13163e58c5f4a45","lessThan":"6aaeec59aadcd1eafc18b049f1b759fb6b9d9569","status":"affected","versionType":"git"},{"version":"d844702198395d3f80222777030f69db6be6b709","lessThan":"9d99b770e7b67b00bdef9005b928aad13e1d679b","status":"affected","versionType":"git"},{"version":"82544d36b1729153c8aeb179e84750f0c085d3b1","lessThan":"ff20d16b2e8230c034e21540043df47222dcc09b","status":"affected","versionType":"git"},{"version":"82544d36b1729153c8aeb179e84750f0c085d3b1","lessThan":"8c0c602202b9a4909b00bc3354e3c0355bc69e65","status":"affected","versionType":"git"},{"version":"cd0e707a927a70cdfd8bc5a512a9719a87f5ed51","status":"affected","versionType":"git"},{"version":"6.6.144","lessThan":"6.6.158","status":"affected","versionType":"semver"},{"version":"6.12.95","lessThan":"6.12.112","status":"affected","versionType":"semver"},{"version":"6.18.38","lessThan":"6.18.54","status":"affected","versionType":"semver"},{"version":"7.0.4","lessThan":"7.1","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"7.1","status":"affected"},{"version":"0","lessThan":"7.1","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.54","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.8","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6aaeec59aadcd1eafc18b049f1b759fb6b9d9569","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"9d99b770e7b67b00bdef9005b928aad13e1d679b","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"8c0c602202b9a4909b00bc3354e3c0355bc69e65","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6.6.158","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6.12.112","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6.18.54","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","source_modified_at":"2026-10-19T09:15:46.038Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"7.1","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00209,"percentile":0.10465,"score_date":"2026-10-23"},"published_at":"2026-10-06T08:44:51.412Z","modified_at":"2026-10-19T09:15:46.038Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98215","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:15:46.038Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98215","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/caa1b913d90d5dc07073733326d2af0f0288f089"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/6aaeec59aadcd1eafc18b049f1b759fb6b9d9569"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/9d99b770e7b67b00bdef9005b928aad13e1d679b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/ff20d16b2e8230c034e21540043df47222dcc09b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/8c0c602202b9a4909b00bc3354e3c0355bc69e65"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:15:46.038Z","content_hash":"1162299922eaa77d82dcb9b5cd94a1e798e4f87ab4124847d80507b505776556"}}