{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-26868", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-19T14:20:24.184Z", "datePublished": "2024-04-17T10:27:29.431Z", "dateUpdated": "2026-08-05T11:27:55.702Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:27:55.702Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfs: fix panic when nfs4_ff_layout_prepare_ds() fails\n\nWe've been seeing the following panic in production\n\nBUG: kernel NULL pointer dereference, address: 0000000000000065\nPGD 2f485f067 P4D 2f485f067 PUD 2cc5d8067 PMD 0\nRIP: 0010:ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles]\nCall Trace:\n \n ? __die+0x78/0xc0\n ? page_fault_oops+0x286/0x380\n ? __rpc_execute+0x2c3/0x470 [sunrpc]\n ? rpc_new_task+0x42/0x1c0 [sunrpc]\n ? exc_page_fault+0x5d/0x110\n ? asm_exc_page_fault+0x22/0x30\n ? ff_layout_free_layoutreturn+0x110/0x110 [nfs_layout_flexfiles]\n ? ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles]\n ? ff_layout_cancel_io+0x6f/0x90 [nfs_layout_flexfiles]\n pnfs_mark_matching_lsegs_return+0x1b0/0x360 [nfsv4]\n pnfs_error_mark_layout_for_return+0x9e/0x110 [nfsv4]\n ? ff_layout_send_layouterror+0x50/0x160 [nfs_layout_flexfiles]\n nfs4_ff_layout_prepare_ds+0x11f/0x290 [nfs_layout_flexfiles]\n ff_layout_pg_init_write+0xf0/0x1f0 [nfs_layout_flexfiles]\n __nfs_pageio_add_request+0x154/0x6c0 [nfs]\n nfs_pageio_add_request+0x26b/0x380 [nfs]\n nfs_do_writepage+0x111/0x1e0 [nfs]\n nfs_writepages_callback+0xf/0x30 [nfs]\n write_cache_pages+0x17f/0x380\n ? nfs_pageio_init_write+0x50/0x50 [nfs]\n ? nfs_writepages+0x6d/0x210 [nfs]\n ? nfs_writepages+0x6d/0x210 [nfs]\n nfs_writepages+0x125/0x210 [nfs]\n do_writepages+0x67/0x220\n ? generic_perform_write+0x14b/0x210\n filemap_fdatawrite_wbc+0x5b/0x80\n file_write_and_wait_range+0x6d/0xc0\n nfs_file_fsync+0x81/0x170 [nfs]\n ? nfs_file_mmap+0x60/0x60 [nfs]\n __x64_sys_fsync+0x53/0x90\n do_syscall_64+0x3d/0x90\n entry_SYSCALL_64_after_hwframe+0x46/0xb0\n\nInspecting the core with drgn I was able to pull this\n\n >>> prog.crashed_thread().stack_trace()[0]\n #0 at 0xffffffffa079657a (ff_layout_cancel_io+0x3a/0x84) in ff_layout_cancel_io at fs/nfs/flexfilelayout/flexfilelayout.c:2021:27\n >>> prog.crashed_thread().stack_trace()[0]['idx']\n (u32)1\n >>> prog.crashed_thread().stack_trace()[0]['flseg'].mirror_array[1].mirror_ds\n (struct nfs4_ff_layout_ds *)0xffffffffffffffed\n\nThis is clear from the stack trace, we call nfs4_ff_layout_prepare_ds()\nwhich could error out initializing the mirror_ds, and then we go to\nclean it all up and our check is only for if (!mirror->mirror_ds). This\nis inconsistent with the rest of the users of mirror_ds, which have\n\n if (IS_ERR_OR_NULL(mirror_ds))\n\nto keep from tripping over this exact scenario. Fix this up in\nff_layout_cancel_io() to make sure we don't panic when we get an error.\nI also spot checked all the other instances of checking mirror_ds and we\nappear to be doing the correct checks everywhere, only unconditionally\ndereferencing mirror_ds when we know it would be valid." } ], "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 vulnerable code path is driven entirely by data from the remote NFS server — a malicious, compromised, or spoofed NFSv4.1/4.2 server forces GETDEVICEINFO to fail (error reply, malformed XDR, or no usable DS addresses), which is what plants the ERR_PTR that is later dereferenced. The NFS client processes this attacker-controlled protocol data over the network with no locality restriction.\nAC:L - The server-side attacker fully and deterministically controls the trigger: grant a flexfiles layout, then fail the GETDEVICEINFO for one of its device IDs, and the very next write/fsync on that inode panics the client. No race, no memory-layout grooming, and the flexfiles layout driver is present in default distro NFSv4.1 configurations.\nPR:N - The attacker acts as the NFS server (or an RPC-reply injector on the path) and needs no credentials or account on the victim client. Even in the purely local framing, any unprivileged user with write access to a file on the mount reaches nfs_writepages()→ff_layout_pg_init_write(), so no elevated privileges are required in any scenario.\nUI:N - No victim action is needed at exploit time — the mount is pre-existing infrastructure, and normal background writeback or any application fsync() drives the path automatically. A compromised server can simply wait for routine client I/O.\nS:U - The fault occurs in the NFS client within the kernel's own security authority; nothing crosses into another VM, hypervisor, or IOMMU/DMA boundary.\nC:N - The dereferenced value can only ever be ERR_PTR(-ENODEV), producing a fixed low address (0x65) below mmap_min_addr that faults immediately. No attacker data is read back and no kernel memory is disclosed.\nI:N - The bug is a read of an invalid fixed pointer with no write to kernel memory and no attacker influence over the faulting address, so there is no data modification or control-flow hijack primitive.\nA:H - The result is an unrecoverable kernel NULL-pointer dereference oops in writeback context (as captured in the production panic in the fix commit), taking down the client system. It can be re-triggered at will by the remote server, so affected clients can be kept permanently down." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfs/flexfilelayout/flexfilelayout.c" ], "versions": [ { "version": "b739a5bd9d9f18cc69dced8db128ef7206e000cd", "lessThan": "31db25e3141b20e2a76a9f219eeca52e3cab126c", "status": "affected", "versionType": "git" }, { "version": "b739a5bd9d9f18cc69dced8db128ef7206e000cd", "lessThan": "7ca651b4ec4a049f5a46a0e5ff921b86b91c47c5", "status": "affected", "versionType": "git" }, { "version": "b739a5bd9d9f18cc69dced8db128ef7206e000cd", "lessThan": "5ada9016b1217498fad876a3d5b07645cc955608", "status": "affected", "versionType": "git" }, { "version": "b739a5bd9d9f18cc69dced8db128ef7206e000cd", "lessThan": "dac068f164ad05b35e7c0be13f138c3f6adca58f", "status": "affected", "versionType": "git" }, { "version": "b739a5bd9d9f18cc69dced8db128ef7206e000cd", "lessThan": "719fcafe07c12646691bd62d7f8d94d657fa0766", "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/nfs/flexfilelayout/flexfilelayout.c" ], "versions": [ { "version": "6.1", "status": "affected" }, { "version": "0", "lessThan": "6.1", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.83", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.23", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.7.11", "lessThanOrEqual": "6.7.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.8.2", "lessThanOrEqual": "6.8.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.9", "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": "6.1", "versionEndExcluding": "6.1.83" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.6.23" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.7.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.8.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/31db25e3141b20e2a76a9f219eeca52e3cab126c" }, { "url": "https://git.kernel.org/stable/c/7ca651b4ec4a049f5a46a0e5ff921b86b91c47c5" }, { "url": "https://git.kernel.org/stable/c/5ada9016b1217498fad876a3d5b07645cc955608" }, { "url": "https://git.kernel.org/stable/c/dac068f164ad05b35e7c0be13f138c3f6adca58f" }, { "url": "https://git.kernel.org/stable/c/719fcafe07c12646691bd62d7f8d94d657fa0766" } ], "title": "nfs: fix panic when nfs4_ff_layout_prepare_ds() fails", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CISA ADP Vulnrichment", "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-26868", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-05-28T19:56:48.883135Z" } } } ], "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-04T17:48:27.644Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-02T00:21:04.259Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/31db25e3141b20e2a76a9f219eeca52e3cab126c", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/7ca651b4ec4a049f5a46a0e5ff921b86b91c47c5", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/5ada9016b1217498fad876a3d5b07645cc955608", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/dac068f164ad05b35e7c0be13f138c3f6adca58f", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/719fcafe07c12646691bd62d7f8d94d657fa0766", "tags": [ "x_transferred" ] } ] } ] } }