{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-46988", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-27T18:42:55.948Z", "datePublished": "2024-02-28T08:13:15.310Z", "dateUpdated": "2026-05-11T13:45:47.021Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T13:45:47.021Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nuserfaultfd: release page in error path to avoid BUG_ON\n\nConsider the following sequence of events:\n\n1. Userspace issues a UFFD ioctl, which ends up calling into\n shmem_mfill_atomic_pte(). We successfully account the blocks, we\n shmem_alloc_page(), but then the copy_from_user() fails. We return\n -ENOENT. We don't release the page we allocated.\n2. Our caller detects this error code, tries the copy_from_user() after\n dropping the mmap_lock, and retries, calling back into\n shmem_mfill_atomic_pte().\n3. Meanwhile, let's say another process filled up the tmpfs being used.\n4. So shmem_mfill_atomic_pte() fails to account blocks this time, and\n immediately returns - without releasing the page.\n\nThis triggers a BUG_ON in our caller, which asserts that the page\nshould always be consumed, unless -ENOENT is returned.\n\nTo fix this, detect if we have such a \"dangling\" page when accounting\nfails, and if so, release it before returning." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/shmem.c" ], "versions": [ { "version": "cb658a453b9327ce96ce5222c24d162b5b65b564", "lessThan": "319116227e52d49eee671f0aa278bac89b3c1b69", "status": "affected", "versionType": "git" }, { "version": "cb658a453b9327ce96ce5222c24d162b5b65b564", "lessThan": "07c9b834c97d0fa3402fb7f3f3b32df370a6ff1f", "status": "affected", "versionType": "git" }, { "version": "cb658a453b9327ce96ce5222c24d162b5b65b564", "lessThan": "b3f1731c6d7fbc1ebe3ed8eff6d6bec56d76ff43", "status": "affected", "versionType": "git" }, { "version": "cb658a453b9327ce96ce5222c24d162b5b65b564", "lessThan": "140cfd9980124aecb6c03ef2e69c72d0548744de", "status": "affected", "versionType": "git" }, { "version": "cb658a453b9327ce96ce5222c24d162b5b65b564", "lessThan": "ad53127973034c63b5348715a1043d0e80ceb330", "status": "affected", "versionType": "git" }, { "version": "cb658a453b9327ce96ce5222c24d162b5b65b564", "lessThan": "2d59a0ed8b26b8f3638d8afc31f839e27759f1f6", "status": "affected", "versionType": "git" }, { "version": "cb658a453b9327ce96ce5222c24d162b5b65b564", "lessThan": "7ed9d238c7dbb1fdb63ad96a6184985151b0171c", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/shmem.c" ], "versions": [ { "version": "4.11", "status": "affected" }, { "version": "0", "lessThan": "4.11", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.233", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.191", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.120", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.38", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.11.22", "lessThanOrEqual": "5.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.12.5", "lessThanOrEqual": "5.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.13", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "4.14.233" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "4.19.191" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "5.4.120" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "5.10.38" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "5.11.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "5.12.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "5.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/319116227e52d49eee671f0aa278bac89b3c1b69" }, { "url": "https://git.kernel.org/stable/c/07c9b834c97d0fa3402fb7f3f3b32df370a6ff1f" }, { "url": "https://git.kernel.org/stable/c/b3f1731c6d7fbc1ebe3ed8eff6d6bec56d76ff43" }, { "url": "https://git.kernel.org/stable/c/140cfd9980124aecb6c03ef2e69c72d0548744de" }, { "url": "https://git.kernel.org/stable/c/ad53127973034c63b5348715a1043d0e80ceb330" }, { "url": "https://git.kernel.org/stable/c/2d59a0ed8b26b8f3638d8afc31f839e27759f1f6" }, { "url": "https://git.kernel.org/stable/c/7ed9d238c7dbb1fdb63ad96a6184985151b0171c" } ], "title": "userfaultfd: release page in error path to avoid BUG_ON", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-06-21T16:28:01.611692Z", "id": "CVE-2021-46988", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-21T16:28:13.369Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T05:24:38.475Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/319116227e52d49eee671f0aa278bac89b3c1b69", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/07c9b834c97d0fa3402fb7f3f3b32df370a6ff1f", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/b3f1731c6d7fbc1ebe3ed8eff6d6bec56d76ff43", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/140cfd9980124aecb6c03ef2e69c72d0548744de", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/ad53127973034c63b5348715a1043d0e80ceb330", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/2d59a0ed8b26b8f3638d8afc31f839e27759f1f6", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/7ed9d238c7dbb1fdb63ad96a6184985151b0171c", "tags": [ "x_transferred" ] } ] } ] } }