{ "dataType": "CVE_RECORD", "cveMetadata": { "cveId": "CVE-2024-26870", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-19T14:20:24.184Z", "datePublished": "2024-04-17T10:27:30.756Z", "dateUpdated": "2026-08-05T11:28:01.958Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:28:01.958Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4.2: fix nfs4_listxattr kernel BUG at mm/usercopy.c:102\n\nA call to listxattr() with a buffer size = 0 returns the actual\nsize of the buffer needed for a subsequent call. When size > 0,\nnfs4_listxattr() does not return an error because either\ngeneric_listxattr() or nfs4_listxattr_nfs4_label() consumes\nexactly all the bytes then size is 0 when calling\nnfs4_listxattr_nfs4_user() which then triggers the following\nkernel BUG:\n\n [ 99.403778] kernel BUG at mm/usercopy.c:102!\n [ 99.404063] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP\n [ 99.408463] CPU: 0 PID: 3310 Comm: python3 Not tainted 6.6.0-61.fc40.aarch64 #1\n [ 99.415827] Call trace:\n [ 99.415985] usercopy_abort+0x70/0xa0\n [ 99.416227] __check_heap_object+0x134/0x158\n [ 99.416505] check_heap_object+0x150/0x188\n [ 99.416696] __check_object_size.part.0+0x78/0x168\n [ 99.416886] __check_object_size+0x28/0x40\n [ 99.417078] listxattr+0x8c/0x120\n [ 99.417252] path_listxattr+0x78/0xe0\n [ 99.417476] __arm64_sys_listxattr+0x28/0x40\n [ 99.417723] invoke_syscall+0x78/0x100\n [ 99.417929] el0_svc_common.constprop.0+0x48/0xf0\n [ 99.418186] do_el0_svc+0x24/0x38\n [ 99.418376] el0_svc+0x3c/0x110\n [ 99.418554] el0t_64_sync_handler+0x120/0x130\n [ 99.418788] el0t_64_sync+0x194/0x198\n [ 99.418994] Code: aa0003e3 d000a3e0 91310000 97f49bdb (d4210000)\n\nIssue is reproduced when generic_listxattr() returns 'system.nfs4_acl',\nthus calling lisxattr() with size = 16 will trigger the bug.\n\nAdd check on nfs4_listxattr() to return ERANGE error when it is\ncalled with size > 0 and the return value is greater than size." } ], "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 - The vulnerability is triggered by a local `listxattr(2)`/`llistxattr(2)`/`flistxattr(2)` syscall on a file residing on an NFSv4 mount; no network peer can initiate it on its own. Although the overflow content is supplied by the NFS server over the wire, a local syscall is required to reach the code, so the attack vector is Local.\nAC:L - Triggering is fully deterministic — the attacker probes with `size = 0`, then calls `listxattr()` with a size exactly equal to the generic handler list (16 bytes for `\"system.nfs4_acl\\0\"`), with no race to win and no memory-layout condition outside their control. The required config (CONFIG_NFS_V4_2, CONFIG_NFS_V4_SECURITY_LABEL, CONFIG_HARDENED_USERCOPY) is enabled by default on mainstream distributions, as demonstrated by the reporter reproducing on a stock Fedora 40 kernel.\nPR:L - Any unprivileged local user with ordinary access to a file on an existing NFSv4.2 mount can call `listxattr()` and set the `user.*` xattrs that become the overflow payload; no capabilities are needed. NFS-mounted home directories on shared/multi-user hosts make this a standard unprivileged-user reach.\nUI:N - The attacker performs every step — setting the xattrs and issuing the sized `listxattr()` call — with no action by any other user. The pre-existing NFS mount is an environmental property of the deployment, not an interaction the attacker must induce.\nS:U - The over-read, the leaked data, and the heap overflow all occur within the kernel's own memory and are delivered to the attacker's own process. No VM, IOMMU, or other security-authority boundary is crossed.\nC:H - When hardened usercopy is not enforcing, `copy_to_user()` transfers up to XATTR_LIST_MAX (64 KB) of kernel heap memory past a 16-byte kmalloc object directly into the attacker's buffer, with the over-read length controlled by how many `user.*` xattrs the attacker attaches to the file. This is a large, attacker-sized disclosure of adjacent slab contents including potential pointers and other tasks' data.\nI:H - The `size_t` underflow hands `nfs4_listxattr_nfs4_user()` a past-the-end pointer with an effectively unbounded length, and `decode_listxattrs()` then memcpy()s `user.\\0` records past the end of a kmalloc-16 object in a loop until EOF. This is a heap buffer overflow with attacker-controlled content, length, and destination slab, which is a strong primitive for adjacent-object corruption and control-flow hijacking.\nA:H - The reported and reproducible outcome is `usercopy_abort()` calling `BUG()` at mm/usercopy.c:102 — a kernel oops that is a full panic on systems with `panic_on_oops` (common on embedded, automotive, and hardened deployments), repeatable at will by any local user. The heap overflow path additionally corrupts slab metadata and adjacent objects, causing further crashes." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nfs/nfs4proc.c" ], "versions": [ { "version": "012a211abd5db098094ce429de5f046368391e68", "lessThan": "4403438eaca6e91f02d272211c4d6b045092396b", "status": "affected", "versionType": "git" }, { "version": "012a211abd5db098094ce429de5f046368391e68", "lessThan": "9d52865ff28245fc2134da9f99baff603a24407a", "status": "affected", "versionType": "git" }, { "version": "012a211abd5db098094ce429de5f046368391e68", "lessThan": "06e828b3f1b206de08ef520fc46a40b22e1869cb", "status": "affected", "versionType": "git" }, { "version": "012a211abd5db098094ce429de5f046368391e68", "lessThan": "79cdcc765969d23f4e3d6ea115660c3333498768", "status": "affected", "versionType": "git" }, { "version": "012a211abd5db098094ce429de5f046368391e68", "lessThan": "80365c9f96015bbf048fdd6c8705d3f8770132bf", "status": "affected", "versionType": "git" }, { "version": "012a211abd5db098094ce429de5f046368391e68", "lessThan": "23bfecb4d852751d5e403557dd500bb563313baf", "status": "affected", "versionType": "git" }, { "version": "012a211abd5db098094ce429de5f046368391e68", "lessThan": "251a658bbfceafb4d58c76b77682c8bf7bcfad65", "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/nfs4proc.c" ], "versions": [ { "version": "5.9", "status": "affected" }, { "version": "0", "lessThan": "5.9", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.214", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.153", "lessThanOrEqual": "5.15.*", "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": "5.9", "versionEndExcluding": "5.10.214" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "5.15.153" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.1.83" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.6.23" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.7.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.8.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9", "versionEndExcluding": "6.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4403438eaca6e91f02d272211c4d6b045092396b" }, { "url": "https://git.kernel.org/stable/c/9d52865ff28245fc2134da9f99baff603a24407a" }, { "url": "https://git.kernel.org/stable/c/06e828b3f1b206de08ef520fc46a40b22e1869cb" }, { "url": "https://git.kernel.org/stable/c/79cdcc765969d23f4e3d6ea115660c3333498768" }, { "url": "https://git.kernel.org/stable/c/80365c9f96015bbf048fdd6c8705d3f8770132bf" }, { "url": "https://git.kernel.org/stable/c/23bfecb4d852751d5e403557dd500bb563313baf" }, { "url": "https://git.kernel.org/stable/c/251a658bbfceafb4d58c76b77682c8bf7bcfad65" } ], "title": "NFSv4.2: fix nfs4_listxattr kernel BUG at mm/usercopy.c:102", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CISA ADP Vulnrichment", "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-26870", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-05-28T19:56:13.503124Z" } } } ], "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-04T17:49:37.605Z" } }, { "providerMetadata": { "orgId": 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"https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html", "tags": [ "x_transferred" ] } ] }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-05-12T11:49:46.342Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem", "versions": [ { "status": "affected", "version": "0", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-265688.html" } ] } ] }, "dataVersion": "5.2" }