{"id":"CVE-2026-98214","revision":"891fa57693c948e3807485dcc185008b","records":[{"revision":"891fa57693c948e3807485dcc185008b","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98214","aliases":[],"title":"selinux: recheck intermediate backing files on mprotect()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: recheck intermediate backing files on mprotect()\n\nmprotect() can be used to bypass the SELinux checks that mmap() performs\nagainst the intermediate layers of a stacked filesystem.\n\nmmap() checks every backing layer as the request descends through the\nstack. mprotect() only has the lowest backing file in vma->vm_file, so it\nrechecks the top-level user and the lowest mounter, but skips the mounters\nof every layer in between. With two nested overlayfs mounts and a policy\ndenying mounter_t -> middle_file_t:file { execute }, a direct\nmmap(PROT_EXEC) is denied:\n\n avc: denied { execute } for pid=71 comm=\"nested_exec\"\n path=\"/payload\" dev=\"overlay\" ino=9\n scontext=user_u:base_r:mounter_t\n tcontext=user_u:object_r:middle_file_t tclass=file permissive=0\n\nwhile mmap(PROT_NONE) followed by mprotect(PROT_EXEC) succeeds.\n\nPreserve each intermediate path, mounter SID and file-description SID in\nthe backing-file security blob, copying the saved entries when another\nbacking layer is opened. Allocate the array only for nested backing files,\nand release it and the path references in the backing_file_free hook.\n\nDuring mprotect(), recheck fd { use } and the requested inode permissions\nfor every saved mounter, and include the intermediate layers in the execmod\nchecks. Policy for nested stacking may then need to grant intermediate\nmounters what a direct mmap() already requires, and execmod on intermediate\nlabels for binaries using text relocations.\n\nTested on arm64 QEMU with a small BusyBox initramfs and a purpose-built\nSELinux policy, on a mainline tree containing\ncommit f2381b546e7e (\"fs: fix user path of nested backing files\").\n\n[PM: subject tweak]","state":0,"publishedAt":"2026-10-06T08:44:50.209+00:00","modifiedAt":"2026-10-19T09:15:45.082+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"security/selinux/hooks.c\",\n \"security/selinux/include/objsec.h\"\n ],\n \"versions\": [\n {\n \"version\": \"bc6c380c1159de52a252ed11f19a42c47f60a735\",\n \"lessThan\": \"4d50ebe5a27724e020747ffd61a051dec67cb8ec\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"8bacd09f12c27710228562e4d13163e58c5f4a45\",\n \"lessThan\": \"89376fbfdcc1a728e1775f98752cdd90b0930a00\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"d844702198395d3f80222777030f69db6be6b709\",\n \"lessThan\": \"d127c7e1f3e1231d8ac8b2738e3f00bea12afe74\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"82544d36b1729153c8aeb179e84750f0c085d3b1\",\n \"lessThan\": \"c2bbb905af2293549651b614a52ad91e0b462b60\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"82544d36b1729153c8aeb179e84750f0c085d3b1\",\n \"lessThan\": \"78fc54b934bfb2c18aad8154c7302067146946f9\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cd0e707a927a70cdfd8bc5a512a9719a87f5ed51\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"6.6.144\",\n \"lessThan\": \"6.6.158\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.95\",\n \"lessThan\": \"6.12.112\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.38\",\n \"lessThan\": \"6.18.54\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.0.4\",\n \"lessThan\": \"7.1\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"security/selinux/hooks.c\",\n \"security/selinux/include/objsec.h\"\n ],\n \"versions\": [\n {\n \"version\": \"7.1\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"7.1\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.158\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.112\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.54\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.8\",\n \"lessThanOrEqual\": \"7.2.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.3\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/4d50ebe5a27724e020747ffd61a051dec67cb8ec","https://git.kernel.org/stable/c/89376fbfdcc1a728e1775f98752cdd90b0930a00","https://git.kernel.org/stable/c/d127c7e1f3e1231d8ac8b2738e3f00bea12afe74","https://git.kernel.org/stable/c/c2bbb905af2293549651b614a52ad91e0b462b60","https://git.kernel.org/stable/c/78fc54b934bfb2c18aad8154c7302067146946f9"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98214","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98214","identifiers":["CVE-2026-98214"]},"retained":false,"historicalAffected":[]}],"coverage":[]}