{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-50755", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-24T13:02:21.544Z", "datePublished": "2025-12-24T13:05:48.928Z", "dateUpdated": "2026-08-05T08:59:41.275Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:59:41.275Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nudf: Avoid double brelse() in udf_rename()\n\nsyzbot reported a warning like below [1]:\n\nVFS: brelse: Trying to free free buffer\nWARNING: CPU: 2 PID: 7301 at fs/buffer.c:1145 __brelse+0x67/0xa0\n...\nCall Trace:\n \n invalidate_bh_lru+0x99/0x150\n smp_call_function_many_cond+0xe2a/0x10c0\n ? generic_remap_file_range_prep+0x50/0x50\n ? __brelse+0xa0/0xa0\n ? __mutex_lock+0x21c/0x12d0\n ? smp_call_on_cpu+0x250/0x250\n ? rcu_read_lock_sched_held+0xb/0x60\n ? lock_release+0x587/0x810\n ? __brelse+0xa0/0xa0\n ? generic_remap_file_range_prep+0x50/0x50\n on_each_cpu_cond_mask+0x3c/0x80\n blkdev_flush_mapping+0x13a/0x2f0\n blkdev_put_whole+0xd3/0xf0\n blkdev_put+0x222/0x760\n deactivate_locked_super+0x96/0x160\n deactivate_super+0xda/0x100\n cleanup_mnt+0x222/0x3d0\n task_work_run+0x149/0x240\n ? task_work_cancel+0x30/0x30\n do_exit+0xb29/0x2a40\n ? reacquire_held_locks+0x4a0/0x4a0\n ? do_raw_spin_lock+0x12a/0x2b0\n ? mm_update_next_owner+0x7c0/0x7c0\n ? rwlock_bug.part.0+0x90/0x90\n ? zap_other_threads+0x234/0x2d0\n do_group_exit+0xd0/0x2a0\n __x64_sys_exit_group+0x3a/0x50\n do_syscall_64+0x34/0xb0\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe cause of the issue is that brelse() is called on both ofibh.sbh\nand ofibh.ebh by udf_find_entry() when it returns NULL. However,\nbrelse() is called by udf_rename(), too. So, b_count on buffer_head\nbecomes unbalanced.\n\nThis patch fixes the issue by not calling brelse() by udf_rename()\nwhen udf_find_entry() returns NULL." } ], "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 bug is reached only through local rename(2)/renameat2 on a mounted UDF filesystem (vfs_rename → udf_rename → udf_find_entry); no network or adjacent protocol handler reaches this path.\nAC:L - A crafted UDF image that makes udf_find_entry() return NULL during rename (as in the syzbot C repro with controlled charset/options) deterministically double-brelse()s the directory buffer_heads with no race or attacker-uncontrollable condition.\nPR:L - UDF lacks FS_USERNS_MOUNT so raw mount needs CAP_SYS_ADMIN, but default UDisks/polkit policy lets an active unprivileged user mount removable UDF media and then rename on that volume, matching CVE-2026-64324.\nUI:N - The attacking local user can mount their own crafted UDF image via UDisks and issue rename themselves; no separate victim action is required.\nS:U - The buffer_head refcount underflow and resulting corruption stay inside the host kernel VFS/UDF authority; this is ordinary same-host kernel impact, not a VM/IOMMU/sandbox boundary cross.\nC:H - Double brelse() underflows a still-cached directory buffer_head reference, yielding a bh_cachep use-after-free whose recycled object contents (b_data, b_page, b_end_io) can be disclosed, consistent with CVE-2024-49882 double-brelse scoring.\nI:H - The same buffer_head UAF exposes b_end_io and list pointers for heap-spray write and control-flow hijack primitives, and can corrupt adjacent page-cache metadata buffers.\nA:H - The unbalanced b_count reproducibly hits WARN in __brelse() (fatal under panic_on_warn) and the resulting use-after-free can oops/panic the kernel during later invalidate/unmount, fully denying availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/udf/namei.c" ], "versions": [ { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "78eba2778ae10fb2a9d450e14d26eb6f6bf1f906", "status": "affected", "versionType": "git" }, { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "9d2cad69547abea961fa80426d600b861de1952b", "status": "affected", "versionType": "git" }, { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "d6da7ec0f94f5208c848e0e94b70f54a0bd9c587", "status": "affected", "versionType": "git" }, { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "156d440dea97deada629bb51cb17887abd862605", "status": "affected", "versionType": "git" }, { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "40dba68d418237b1ae2beaa06d46a94dd946278e", "status": "affected", "versionType": "git" }, { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "e7a6a53c871460727be09f4414ccb29fb8697526", "status": "affected", "versionType": "git" }, { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "4fca09045509f5bde8fc28e68fbca38cb4bdcf2e", "status": "affected", "versionType": "git" }, { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "090bf49833c51da297ec74f98ad2bf44daea9311", "status": "affected", "versionType": "git" }, { "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31", "lessThan": "c791730f2554a9ebb8f18df9368dc27d4ebc38c2", "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/udf/namei.c" ], "versions": [ { "version": "4.2", "status": "affected" }, { "version": "0", "lessThan": "4.2", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.337", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.303", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.270", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.229", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.163", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.86", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.0.16", "lessThanOrEqual": "6.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.2", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2", "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": "4.2", "versionEndExcluding": "4.9.337" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "4.14.303" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "4.19.270" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.4.229" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.10.163" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "5.15.86" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.0.16" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.1.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/78eba2778ae10fb2a9d450e14d26eb6f6bf1f906" }, { "url": "https://git.kernel.org/stable/c/9d2cad69547abea961fa80426d600b861de1952b" }, { "url": "https://git.kernel.org/stable/c/d6da7ec0f94f5208c848e0e94b70f54a0bd9c587" }, { "url": "https://git.kernel.org/stable/c/156d440dea97deada629bb51cb17887abd862605" }, { "url": "https://git.kernel.org/stable/c/40dba68d418237b1ae2beaa06d46a94dd946278e" }, { "url": "https://git.kernel.org/stable/c/e7a6a53c871460727be09f4414ccb29fb8697526" }, { "url": "https://git.kernel.org/stable/c/4fca09045509f5bde8fc28e68fbca38cb4bdcf2e" }, { "url": "https://git.kernel.org/stable/c/090bf49833c51da297ec74f98ad2bf44daea9311" }, { "url": "https://git.kernel.org/stable/c/c791730f2554a9ebb8f18df9368dc27d4ebc38c2" } ], "title": "udf: Avoid double brelse() in udf_rename()", "x_generator": { "engine": "bippy-1.2.0" } } } }