{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47307","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-05-21T13:27:52.133Z","datePublished":"2024-05-21T14:35:26.667Z","dateUpdated":"2026-08-05T08:47:11.403Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T08:47:11.403Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: prevent NULL deref in cifs_compose_mount_options()\n\nThe optional @ref parameter might contain an NULL node_name, so\nprevent dereferencing it in cifs_compose_mount_options().\n\nAddresses-Coverity: 1476408 (\"Explicit null dereferenced\")"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The NULL deref is in CIFS client DFS referral handling (cifs_compose_mount_options via expand_dfs_referral/do_dfs_failover in cifs_mount), which processes attacker-controlled referral data from a remote SMB/DFS peer over the network, matching other malicious-server CIFS client scores.\nAC:L - Once the client mounts or chases DFS against a referral with a NULL node_name, cifs_build_devname(ref->node_name) deterministically faults with no race or other condition outside the attacker's influence.\nPR:N - The attacker is the malicious or compromised SMB/DFS server and needs no privileges or credentials on the victim host; referral processing runs as part of normal client mount/DFS handling.\nUI:N - In the worst reasonable deployment (fstab/autofs/cifsroot DFS mounts, or automounted DFS junctions under an already-mounted root that re-enter cifs_mount), mount-time referral expansion runs without an exploit-time interactive victim action.\nS:U - A kernel oops in the host CIFS client stays within the same OS security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:N - This is a pure NULL pointer dereference of ref->node_name with no out-of-bounds read, UAF, or other information-disclosure primitive.\nI:N - The defect only crashes on NULL dereference in cifs_build_devname; it does not corrupt memory or provide a write or code-execution primitive.\nA:H - Dereferencing NULL node_name causes a kernel oops/panic during DFS mount option composition, fully denying availability and repeatable on subsequent mounts/referral chases."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/cifs/cifs_dfs_ref.c"],"versions":[{"version":"2c55608f28444c3f33b10312881384c470ceed56","lessThan":"f7d1fa65e74263d11f90ddd33b4d4cd905a93759","status":"affected","versionType":"git"},{"version":"2c55608f28444c3f33b10312881384c470ceed56","lessThan":"e58c162789becede894d3e94c0ce6695a2ef5796","status":"affected","versionType":"git"},{"version":"2c55608f28444c3f33b10312881384c470ceed56","lessThan":"ae3d181f4e912f51af7776ea165f199b16fc165d","status":"affected","versionType":"git"},{"version":"2c55608f28444c3f33b10312881384c470ceed56","lessThan":"03313d1c3a2f086bb60920607ab79ac8f8578306","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/cifs/cifs_dfs_ref.c"],"versions":[{"version":"2.6.28","status":"affected"},{"version":"0","lessThan":"2.6.28","status":"unaffected","versionType":"semver"},{"version":"5.4.135","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.53","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.13.5","lessThanOrEqual":"5.13.*","status":"unaffected","versionType":"semver"},{"version":"5.14","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":"2.6.28","versionEndExcluding":"5.4.135"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.28","versionEndExcluding":"5.10.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.28","versionEndExcluding":"5.13.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.28","versionEndExcluding":"5.14"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/f7d1fa65e74263d11f90ddd33b4d4cd905a93759"},{"url":"https://git.kernel.org/stable/c/e58c162789becede894d3e94c0ce6695a2ef5796"},{"url":"https://git.kernel.org/stable/c/ae3d181f4e912f51af7776ea165f199b16fc165d"},{"url":"https://git.kernel.org/stable/c/03313d1c3a2f086bb60920607ab79ac8f8578306"}],"title":"cifs: prevent NULL deref in cifs_compose_mount_options()","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2024-06-12T15:23:12.230114Z","id":"CVE-2021-47307","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":"2024-06-12T15:23:18.690Z"}},{"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2024-08-04T05:32:08.503Z"},"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/f7d1fa65e74263d11f90ddd33b4d4cd905a93759","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/e58c162789becede894d3e94c0ce6695a2ef5796","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/ae3d181f4e912f51af7776ea165f199b16fc165d","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/03313d1c3a2f086bb60920607ab79ac8f8578306","tags":["x_transferred"]}]}]}}