{"id":"CVE-2021-47218","state":"PUBLISHED","title":"selinux: fix NULL-pointer dereference when hashtab allocation fails","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: fix NULL-pointer dereference when hashtab allocation fails\n\nWhen the hash table slot array allocation fails in hashtab_init(),\nh->size is left initialized with a non-zero value, but the h->htable\npointer is NULL. This may then cause a NULL pointer dereference, since\nthe policydb code relies on the assumption that even after a failed\nhashtab_init(), hashtab_map() and hashtab_destroy() can be safely called\non it. Yet, these detect an empty hashtab only by looking at the size.\n\nFix this by making sure that hashtab_init() always leaves behind a valid\nempty hashtab when the allocation fails.","publishedAt":"2024-04-10T19:01:57.060Z","updatedAt":"2026-05-11T13:50:16.030Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"03414a49ad5f3c56988c36d2070e402ffa17feaf","status":"affected","lessThan":"b17dd53cac769dd13031b0ca34f90cc65e523fab","versionType":"git"},{"version":"03414a49ad5f3c56988c36d2070e402ffa17feaf","status":"affected","lessThan":"83c8ab8503adf56bf68dafc7a382f4946c87da79","versionType":"git"},{"version":"03414a49ad5f3c56988c36d2070e402ffa17feaf","status":"affected","lessThan":"dc27f3c5d10c58069672215787a96b4fae01818b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/selinux/ss/hashtab.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.8","versionType":"semver"},{"version":"5.10.82","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.5","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"5.16","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/selinux/ss/hashtab.c"]}],"references":["https://git.kernel.org/stable/c/b17dd53cac769dd13031b0ca34f90cc65e523fab","https://git.kernel.org/stable/c/83c8ab8503adf56bf68dafc7a382f4946c87da79","https://git.kernel.org/stable/c/dc27f3c5d10c58069672215787a96b4fae01818b"],"weaknesses":[],"ingestedAt":"2026-10-29T19:49:19.404Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/47xxx/CVE-2021-47218.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47218","state":"PUBLISHED","datePublished":"2024-04-10T19:01:57.060Z","dateUpdated":"2026-05-11T13:50:16.030Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-04-10T18:59:19.528Z"},"containers":{"cna":{"title":"selinux: fix NULL-pointer dereference when hashtab allocation fails","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nselinux: fix NULL-pointer dereference when hashtab allocation fails\n\nWhen the hash table slot array allocation fails in hashtab_init(),\nh->size is left initialized with a non-zero value, but the h->htable\npointer is NULL. This may then cause a NULL pointer dereference, since\nthe policydb code relies on the assumption that even after a failed\nhashtab_init(), hashtab_map() and hashtab_destroy() can be safely called\non it. Yet, these detect an empty hashtab only by looking at the size.\n\nFix this by making sure that hashtab_init() always leaves behind a valid\nempty hashtab when the allocation fails."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"03414a49ad5f3c56988c36d2070e402ffa17feaf","status":"affected","lessThan":"b17dd53cac769dd13031b0ca34f90cc65e523fab","versionType":"git"},{"version":"03414a49ad5f3c56988c36d2070e402ffa17feaf","status":"affected","lessThan":"83c8ab8503adf56bf68dafc7a382f4946c87da79","versionType":"git"},{"version":"03414a49ad5f3c56988c36d2070e402ffa17feaf","status":"affected","lessThan":"dc27f3c5d10c58069672215787a96b4fae01818b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/selinux/ss/hashtab.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.8","versionType":"semver"},{"version":"5.10.82","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.5","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"5.16","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["security/selinux/ss/hashtab.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b17dd53cac769dd13031b0ca34f90cc65e523fab"},{"url":"https://git.kernel.org/stable/c/83c8ab8503adf56bf68dafc7a382f4946c87da79"},{"url":"https://git.kernel.org/stable/c/dc27f3c5d10c58069672215787a96b4fae01818b"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T13:50:16.030Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"5.10.82"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"5.15.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.8","versionEndExcluding":"5.16"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2024-04-15T15:01:50.328604Z","id":"CVE-2021-47218","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-07-03T17:45:07.734Z"}},{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/b17dd53cac769dd13031b0ca34f90cc65e523fab","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/83c8ab8503adf56bf68dafc7a382f4946c87da79","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/dc27f3c5d10c58069672215787a96b4fae01818b","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-04T05:32:07.363Z"}}]}}}