{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-53216", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-11-19T17:17:25.024Z", "datePublished": "2024-12-27T13:50:01.869Z", "dateUpdated": "2026-08-05T11:44:41.267Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:44:41.267Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: release svc_expkey/svc_export with rcu_work\n\nThe last reference for `cache_head` can be reduced to zero in `c_show`\nand `e_show`(using `rcu_read_lock` and `rcu_read_unlock`). Consequently,\n`svc_export_put` and `expkey_put` will be invoked, leading to two\nissues:\n\n1. The `svc_export_put` will directly free ex_uuid. However,\n `e_show`/`c_show` will access `ex_uuid` after `cache_put`, which can\n trigger a use-after-free issue, shown below.\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in svc_export_show+0x362/0x430 [nfsd]\n Read of size 1 at addr ff11000010fdc120 by task cat/870\n\n CPU: 1 UID: 0 PID: 870 Comm: cat Not tainted 6.12.0-rc3+ #1\n Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n 1.16.1-2.fc37 04/01/2014\n Call Trace:\n \n dump_stack_lvl+0x53/0x70\n print_address_description.constprop.0+0x2c/0x3a0\n print_report+0xb9/0x280\n kasan_report+0xae/0xe0\n svc_export_show+0x362/0x430 [nfsd]\n c_show+0x161/0x390 [sunrpc]\n seq_read_iter+0x589/0x770\n seq_read+0x1e5/0x270\n proc_reg_read+0xe1/0x140\n vfs_read+0x125/0x530\n ksys_read+0xc1/0x160\n do_syscall_64+0x5f/0x170\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\n Allocated by task 830:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x14/0x30\n __kasan_kmalloc+0x8f/0xa0\n __kmalloc_node_track_caller_noprof+0x1bc/0x400\n kmemdup_noprof+0x22/0x50\n svc_export_parse+0x8a9/0xb80 [nfsd]\n cache_do_downcall+0x71/0xa0 [sunrpc]\n cache_write_procfs+0x8e/0xd0 [sunrpc]\n proc_reg_write+0xe1/0x140\n vfs_write+0x1a5/0x6d0\n ksys_write+0xc1/0x160\n do_syscall_64+0x5f/0x170\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\n Freed by task 868:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x14/0x30\n kasan_save_free_info+0x3b/0x60\n __kasan_slab_free+0x37/0x50\n kfree+0xf3/0x3e0\n svc_export_put+0x87/0xb0 [nfsd]\n cache_purge+0x17f/0x1f0 [sunrpc]\n nfsd_destroy_serv+0x226/0x2d0 [nfsd]\n nfsd_svc+0x125/0x1e0 [nfsd]\n write_threads+0x16a/0x2a0 [nfsd]\n nfsctl_transaction_write+0x74/0xa0 [nfsd]\n vfs_write+0x1a5/0x6d0\n ksys_write+0xc1/0x160\n do_syscall_64+0x5f/0x170\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\n2. We cannot sleep while using `rcu_read_lock`/`rcu_read_unlock`.\n However, `svc_export_put`/`expkey_put` will call path_put, which\n subsequently triggers a sleeping operation due to the following\n `dput`.\n\n =============================\n WARNING: suspicious RCU usage\n 5.10.0-dirty #141 Not tainted\n -----------------------------\n ...\n Call Trace:\n dump_stack+0x9a/0xd0\n ___might_sleep+0x231/0x240\n dput+0x39/0x600\n path_put+0x1b/0x30\n svc_export_put+0x17/0x80\n e_show+0x1c9/0x200\n seq_read_iter+0x63f/0x7c0\n seq_read+0x226/0x2d0\n vfs_read+0x113/0x2c0\n ksys_read+0xc9/0x170\n do_syscall_64+0x33/0x40\n entry_SYSCALL_64_after_hwframe+0x67/0xd1\n\nFix these issues by using `rcu_work` to help release\n`svc_expkey`/`svc_export`. This approach allows for an asynchronous\ncontext to invoke `path_put` and also facilitates the freeing of\n`uuid/exp/key` after an RCU grace period." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Although the affected subsystem is nfsd, the vulnerable use-after-free is only reachable through a local `read(2)` on `/proc/fs/nfs/exports`, `/proc/fs/nfsd/exports` or `/proc/net/rpc/*/content`; a remote NFS client can drive the freeing half of the race but cannot reach `e_show`/`c_show` itself. Exploitation therefore requires local access.\nAC:L - The attacker fully controls the reader side with an unbounded, unrate-limited read loop, and can actively drive the freeing side because `nfsd_set_fh_dentry()` performs the export-cache lookup and refresh upcall before any secure-port or access check, on top of the routine `cache_clean()`/`sunrpc_cache_update()`/flush churn on any live NFS server. Controlling both halves of the race makes it reliably winnable.\nPR:L - `/proc/fs/nfsd/exports` and `/proc/fs/nfsd/export_stats` are registered `S_IRUGO`, and `/proc/fs/nfs/exports` is created with mode 0 which procfs promotes to 0444, so any unprivileged local user can read them. No capability, namespace trick, or group membership is needed.\nUI:N - The attacker simply reads a world-readable procfs file in a loop; no victim action, mount, or administrator involvement is required.\nS:U - The corruption and its consequences are confined to the kernel's own memory within a single security authority, with no VM, IOMMU, or sandbox boundary crossed.\nC:H - The freed `ex_uuid`, `ex_client->name`, `ex_path` dentry chain and `ex_fslocs.locations[]` pointer array are read and copied verbatim into the seq_file buffer returned to the unprivileged reader, so heap grooming of the freed slabs yields disclosure of arbitrary kernel memory to userspace.\nI:H - This is a use-after-free on attacker-groomable slab objects, and the reader performs writes into the freed memory — `percpu_counter_sum_positive()` takes `raw_spin_lock_irqsave` on the kfree'd `ex_stats`, and `dput`/`mntput` decrement refcounts on freed dentries/mounts — giving corruption primitives suitable for privilege escalation.\nA:H - The bug is a KASAN-confirmed slab use-after-free that oopses, plus a NULL dereference when `fsloc->locations` is cleared while `locations_count` remains non-zero, and `dput()` sleeping inside an RCU read-side critical section causing scheduling-while-atomic and RCU stalls — all kernel crashes." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfsd/export.c", "fs/nfsd/export.h" ], "versions": [ { "version": "9ceddd9da13434a5906255c0fc528c385aded283", "lessThan": "bd8524148dd8c123334b066faa90590ba2ef8e6f", "status": "affected", "versionType": "git" }, { "version": "9ceddd9da13434a5906255c0fc528c385aded283", "lessThan": "2e4854599200f4d021df8ae17e69221d7c149f3e", "status": "affected", "versionType": "git" }, { "version": "9ceddd9da13434a5906255c0fc528c385aded283", "lessThan": "ad4363a24a5746b257c0beb5d8cc68f9b62c173f", "status": "affected", "versionType": "git" }, { "version": "9ceddd9da13434a5906255c0fc528c385aded283", "lessThan": "f8c989a0c89a75d30f899a7cabdc14d72522bb8d", "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/nfsd/export.c", "fs/nfsd/export.h" ], "versions": [ { "version": "4.20", "status": "affected" }, { "version": "0", "lessThan": "4.20", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.64", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.11.11", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.2", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13", "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": "4.20", "versionEndExcluding": "6.6.64" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.11.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.12.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "6.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/bd8524148dd8c123334b066faa90590ba2ef8e6f" }, { "url": "https://git.kernel.org/stable/c/2e4854599200f4d021df8ae17e69221d7c149f3e" }, { "url": "https://git.kernel.org/stable/c/ad4363a24a5746b257c0beb5d8cc68f9b62c173f" }, { "url": "https://git.kernel.org/stable/c/f8c989a0c89a75d30f899a7cabdc14d72522bb8d" } ], "title": "nfsd: release svc_expkey/svc_export with rcu_work", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2024-53216", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-02-11T15:43:16.959079Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-02-11T15:45:26.202Z" } } ] } }