{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-68774", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-24T10:30:51.035Z", "datePublished": "2026-01-13T15:28:51.379Z", "dateUpdated": "2026-08-05T12:11:24.278Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:11:24.278Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfsplus: fix missing hfs_bnode_get() in __hfs_bnode_create\n\nWhen sync() and link() are called concurrently, both threads may\nenter hfs_bnode_find() without finding the node in the hash table\nand proceed to create it.\n\nThread A:\n hfsplus_write_inode()\n -> hfsplus_write_system_inode()\n -> hfs_btree_write()\n -> hfs_bnode_find(tree, 0)\n -> __hfs_bnode_create(tree, 0)\n\nThread B:\n hfsplus_create_cat()\n -> hfs_brec_insert()\n -> hfs_bnode_split()\n -> hfs_bmap_alloc()\n -> hfs_bnode_find(tree, 0)\n -> __hfs_bnode_create(tree, 0)\n\nIn this case, thread A creates the bnode, sets refcnt=1, and hashes it.\nThread B also tries to create the same bnode, notices it has already\nbeen inserted, drops its own instance, and uses the hashed one without\ngetting the node.\n\n```\n\n\tnode2 = hfs_bnode_findhash(tree, cnid);\n\tif (!node2) { <- Thread A\n\t\thash = hfs_bnode_hash(cnid);\n\t\tnode->next_hash = tree->node_hash[hash];\n\t\ttree->node_hash[hash] = node;\n\t\ttree->node_hash_cnt++;\n\t} else { <- Thread B\n\t\tspin_unlock(&tree->hash_lock);\n\t\tkfree(node);\n\t\twait_event(node2->lock_wq,\n\t\t\t!test_bit(HFS_BNODE_NEW, &node2->flags));\n\t\treturn node2;\n\t}\n```\n\nHowever, hfs_bnode_find() requires each call to take a reference.\nHere both threads end up setting refcnt=1. When they later put the node,\nthis triggers:\n\nBUG_ON(!atomic_read(&node->refcnt))\n\nIn this scenario, Thread B in fact finds the node in the hash table\nrather than creating a new one, and thus must take a reference.\n\nFix this by calling hfs_bnode_get() when reusing a bnode newly created by\nanother thread to ensure the refcount is updated correctly.\n\nA similar bug was fixed in HFS long ago in commit\na9dc087fd3c4 (\"fix missing hfs_bnode_get() in __hfs_bnode_create\")\nbut the same issue remained in HFS+ until now." } ], "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 - A guest-writable ksmbd share backed by HFS+ lets a remote SMB2 client issue FILE_LINK_INFORMATION, which reaches hfsplus_link() and the vulnerable B-tree allocation path.\nAC:L - The attacker can prime the catalog B-tree and drive concurrent hard-link operations and dirty writeback; no uncontrollable memory layout or rare configuration is required.\nPR:N - A guest-writable SMB share permits an anonymous session to operate as a write-capable guest identity without credentials or capabilities.\nUI:N - Once the HFS+ volume is mounted and exported, attacker requests and kernel writeback trigger the race without victim action.\nS:U - The vulnerability and resulting kernel failure remain within the host kernel's security authority and do not cross a virtualization or isolation boundary.\nC:N - The losing creator frees only its private duplicate, while the shared header node remains hashed; the bug provides no information-disclosure primitive.\nI:N - The raced node is the non-deletable B-tree header, and BUG_ON occurs before a negative decrement, so there is no demonstrated UAF, arbitrary write, or memory corruption.\nA:H - The missing reference causes a subsequent hfs_bnode_put() to hit BUG_ON and oops a writeback worker, potentially panicking the entire host when panic-on-oops is enabled." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/hfsplus/bnode.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "3b0fc7af50b896d0f3d104e70787ba1973bc0b56", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "39e149d58ef4d7883cbf87448d39d51292fd342d", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "b68dc4134b18a3922cd33439ec614aad4172bc86", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "b9d1c6bb5f19460074ce9862cb80be86b5fb0a50", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "457f795e7abd7770de10216d7f9994a3f12a56d6", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "5882e7c8cdbb5e254a69628b780acff89c78071e", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "152af114287851583cf7e0abc10129941f19466a", "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/hfsplus/bnode.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.248", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.198", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.160", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.120", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.64", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.3", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19", "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": "2.6.12", "versionEndExcluding": "5.10.248" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.15.198" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.1.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.120" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.64" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.18.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3b0fc7af50b896d0f3d104e70787ba1973bc0b56" }, { "url": "https://git.kernel.org/stable/c/39e149d58ef4d7883cbf87448d39d51292fd342d" }, { "url": "https://git.kernel.org/stable/c/b68dc4134b18a3922cd33439ec614aad4172bc86" }, { "url": "https://git.kernel.org/stable/c/b9d1c6bb5f19460074ce9862cb80be86b5fb0a50" }, { "url": "https://git.kernel.org/stable/c/457f795e7abd7770de10216d7f9994a3f12a56d6" }, { "url": "https://git.kernel.org/stable/c/5882e7c8cdbb5e254a69628b780acff89c78071e" }, { "url": "https://git.kernel.org/stable/c/152af114287851583cf7e0abc10129941f19466a" } ], "title": "hfsplus: fix missing hfs_bnode_get() in __hfs_bnode_create", "x_generator": { "engine": "bippy-1.2.0" } } } }