{"id":"CVE-2021-47342","state":"PUBLISHED","title":"ext4: fix possible UAF when remounting r/o a mmp-protected file system","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix possible UAF when remounting r/o a mmp-protected file system\n\nAfter commit 618f003199c6 (\"ext4: fix memory leak in\next4_fill_super\"), after the file system is remounted read-only, there\nis a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to\npoint at freed memory, which the call to ext4_stop_mmpd() can trip\nover.\n\nFix this by only allowing kmmpd() to exit when it is stopped via\next4_stop_mmpd().\n\nBug-Report-Link: <20210629143603.2166962-1-yebin10@huawei.com>","publishedAt":"2024-05-21T14:35:49.643Z","updatedAt":"2026-05-23T15:19:46.440Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5e4f5138bd8522ebe231a137682d3857209a2c07","status":"affected","lessThan":"b663890d854403e566169f7e90aed5cd6ff64f6b","versionType":"git"},{"version":"eb7b40d9d3785f7a131fb0b1f89bb6efa46c1833","status":"affected","lessThan":"7ed572cdf11081f8f9e07abd4bea56a3f2c4edbd","versionType":"git"},{"version":"618f003199c6188e01472b03cdbba227f1dc5f24","status":"affected","lessThan":"61bb4a1c417e5b95d9edb4f887f131de32e419cb","versionType":"git"},{"version":"cecfdb9cf9a700d1037066173abac0617f6788df","status":"affected","versionType":"git"},{"version":"5.12.18","status":"affected","lessThan":"5.13","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/mmp.c","fs/ext4/super.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5.10.51","status":"affected","lessThan":"5.10.77","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/mmp.c","fs/ext4/super.c"]}],"references":["https://git.kernel.org/stable/c/b663890d854403e566169f7e90aed5cd6ff64f6b","https://git.kernel.org/stable/c/7ed572cdf11081f8f9e07abd4bea56a3f2c4edbd","https://git.kernel.org/stable/c/61bb4a1c417e5b95d9edb4f887f131de32e419cb"],"weaknesses":[],"ingestedAt":"2026-10-29T19:49:19.404Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/47xxx/CVE-2021-47342.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47342","state":"PUBLISHED","datePublished":"2024-05-21T14:35:49.643Z","dateUpdated":"2026-05-23T15:19:46.440Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-05-21T14:28:16.979Z"},"containers":{"cna":{"title":"ext4: fix possible UAF when remounting r/o a mmp-protected file system","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix possible UAF when remounting r/o a mmp-protected file system\n\nAfter commit 618f003199c6 (\"ext4: fix memory leak in\next4_fill_super\"), after the file system is remounted read-only, there\nis a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to\npoint at freed memory, which the call to ext4_stop_mmpd() can trip\nover.\n\nFix this by only allowing kmmpd() to exit when it is stopped via\next4_stop_mmpd().\n\nBug-Report-Link: <20210629143603.2166962-1-yebin10@huawei.com>"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5e4f5138bd8522ebe231a137682d3857209a2c07","status":"affected","lessThan":"b663890d854403e566169f7e90aed5cd6ff64f6b","versionType":"git"},{"version":"eb7b40d9d3785f7a131fb0b1f89bb6efa46c1833","status":"affected","lessThan":"7ed572cdf11081f8f9e07abd4bea56a3f2c4edbd","versionType":"git"},{"version":"618f003199c6188e01472b03cdbba227f1dc5f24","status":"affected","lessThan":"61bb4a1c417e5b95d9edb4f887f131de32e419cb","versionType":"git"},{"version":"cecfdb9cf9a700d1037066173abac0617f6788df","status":"affected","versionType":"git"},{"version":"5.12.18","status":"affected","lessThan":"5.13","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/mmp.c","fs/ext4/super.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5.10.51","status":"affected","lessThan":"5.10.77","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/ext4/mmp.c","fs/ext4/super.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b663890d854403e566169f7e90aed5cd6ff64f6b"},{"url":"https://git.kernel.org/stable/c/7ed572cdf11081f8f9e07abd4bea56a3f2c4edbd"},{"url":"https://git.kernel.org/stable/c/61bb4a1c417e5b95d9edb4f887f131de32e419cb"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-23T15:19:46.440Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.51","versionEndExcluding":"5.10.77"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12.18"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA 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