{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-46052", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-46052", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-05-27T12:57:10.777Z", "updatedAt": "2026-10-19T19:26:42.195Z", "importedAt": "2026-10-24T01:58:14.884Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "ceph: only d_add() negative dentries when they are unhashed", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: only d_add() negative dentries when they are unhashed\n\nCeph can call d_add(dentry, NULL) on a negative dentry that is already\npresent in the primary dcache hash.\n\nIn the current VFS that is not safe. d_add() goes through __d_add()\nto __d_rehash(), which unconditionally reinserts dentry->d_hash into\nthe hlist_bl bucket. If the dentry is already hashed, reinserting the\nsame node can corrupt the bucket, including creating a self-loop.\nOnce that happens, __d_lookup() can spin forever in the hlist_bl walk,\ntypically looping only on the d_name.hash mismatch check and\neventually triggering RCU stall reports like this one:\n\n rcu: INFO: rcu_sched self-detected stall on CPU\n rcu: 87-....: (2100 ticks this GP) idle=3a4c/1/0x4000000000000000 softirq=25003319/25003319 fqs=829\n rcu: (t=2101 jiffies g=79058445 q=698988 ncpus=192)\n CPU: 87 UID: 2952868916 PID: 3933303 Comm: php-cgi8.3 Not tainted 6.18.17-i1-amd #950 NONE\n Hardware name: Dell Inc. PowerEdge R7615/0G9DHV, BIOS 1.6.6 09/22/2023\n RIP: 0010:__d_lookup+0x46/0xb0\n Code: c1 e8 07 48 8d 04 c2 48 8b 00 49 89 fc 49 89 f5 48 89 c3 48 83 e3 fe 48 83 f8 01 77 0f eb 2d 0f 1f 44 00 00 48 8b 1b 48 85 db <74> 20 39 6b 18 75 f3 48 8d 7b 78 e8 ba 85 d0 00 4c 39 63 10 74 1f\n RSP: 0018:ff745a70c8253898 EFLAGS: 00000282\n RAX: ff26e470054cb208 RBX: ff26e470054cb208 RCX: 000000006e958966\n RDX: ff26e48267340000 RSI: ff745a70c82539b0 RDI: ff26e458f74655c0\n RBP: 000000006e958966 R08: 0000000000000180 R09: 9cd08d909b919a89\n R10: ff26e458f74655c0 R11: 0000000000000000 R12: ff26e458f74655c0\n R13: ff745a70c82539b0 R14: d0d0d0d0d0d0d0d0 R15: 2f2f2f2f2f2f2f2f\n FS: 00007f5770896980(0000) GS:ff26e482c5d88000(0000) knlGS:0000000000000000\n CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n CR2: 00007f5764de50c0 CR3: 000000a72abb5001 CR4: 0000000000771ef0\n PKRU: 55555554\n Call Trace:\n \n lookup_fast+0x9f/0x100\n walk_component+0x1f/0x150\n link_path_walk+0x20e/0x3d0\n path_lookupat+0x68/0x180\n filename_lookup+0xdc/0x1e0\n vfs_statx+0x6c/0x140\n vfs_fstatat+0x67/0xa0\n __do_sys_newfstatat+0x24/0x60\n do_syscall_64+0x6a/0x230\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nThis is reachable with reused cached negative dentries. A Ceph lookup\nor atomic_open can be handed a negative dentry that is already hashed,\nand fs/ceph/dir.c then hits one of two paths that incorrectly assume\n\"negative\" also means \"unhashed\":\n\n - ceph_finish_lookup():\n MDS reply is -ENOENT with no trace\n -> d_add(dentry, NULL)\n\n - ceph_lookup():\n local ENOENT fast path for a complete directory with shared caps\n -> d_add(dentry, NULL)\n\nBoth paths can therefore re-add an already-hashed negative dentry.\n\nCeph already uses the correct pattern elsewhere: ceph_fill_trace() only\ncalls d_add(dn, NULL) for a negative null-dentry reply when d_unhashed(dn)\nis true.\n\nFix both fs/ceph/dir.c sites the same way: only call d_add() for a\nnegative dentry when it is actually unhashed. If the negative dentry\nis already hashed, leave it in place and reuse it as-is.\n\nThis preserves the existing behavior for unhashed dentries while\navoiding d_hash list corruption for reused hashed negatives.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef", "status": "affected", "versionType": "git", "lessThan": "4147ae08824cc8b65d2b2018f79d416af2937108" }, { "version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef", "status": "affected", "versionType": "git", "lessThan": "73b47a1f06dee5e61b00dee5227d75d3f1f6d977" }, { "version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef", "status": "affected", "versionType": "git", "lessThan": "79ffcbeac6bc1dc1bcdb0434acf250f6215ec111" }, { "version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef", "status": "affected", "versionType": "git", "lessThan": "83ce43a21bb7df8dd52228afdd918d2d058eefde" }, { "version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef", "status": "affected", "versionType": "git", "lessThan": "4179cc390dacebc87079419ec92f86f3dc46294d" }, { "version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef", "status": "affected", "versionType": "git", "lessThan": "b91e535f208c48a5e7464f1aa38338a30e7912df" }, { "version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef", "status": "affected", "versionType": "git", "lessThan": "2010cb06b9df7d3c816c78358c566bdacbdf38ff" }, { "version": "2817b000b02c5f0c05af67c01fb2684e1381d6ef", "status": "affected", "versionType": "git", "lessThan": "803447f93d75ab6e40c85e6d12b5630d281d70d6" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.34", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.34" }, { "version": "5.10.259", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.210", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.176", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.140", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.86", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.27", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.0.4", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.0.*" }, { "version": "7.1", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }