{ "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-2024-49868", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2024-49868", "idYear": 2024, "status": "PUBLISHED", "publishedAt": "2024-10-21T18:01:10.722Z", "updatedAt": "2026-05-11T20:40:47.334Z", "importedAt": "2026-10-24T01:57:16.009Z", "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": "btrfs: fix a NULL pointer dereference when failed to start a new trasacntion", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix a NULL pointer dereference when failed to start a new trasacntion\n\n[BUG]\nSyzbot reported a NULL pointer dereference with the following crash:\n\n FAULT_INJECTION: forcing a failure.\n start_transaction+0x830/0x1670 fs/btrfs/transaction.c:676\n prepare_to_relocate+0x31f/0x4c0 fs/btrfs/relocation.c:3642\n relocate_block_group+0x169/0xd20 fs/btrfs/relocation.c:3678\n ...\n BTRFS info (device loop0): balance: ended with status: -12\n Oops: general protection fault, probably for non-canonical address 0xdffffc00000000cc: 0000 [#1] PREEMPT SMP KASAN NOPTI\n KASAN: null-ptr-deref in range [0x0000000000000660-0x0000000000000667]\n RIP: 0010:btrfs_update_reloc_root+0x362/0xa80 fs/btrfs/relocation.c:926\n Call Trace:\n \n commit_fs_roots+0x2ee/0x720 fs/btrfs/transaction.c:1496\n btrfs_commit_transaction+0xfaf/0x3740 fs/btrfs/transaction.c:2430\n del_balance_item fs/btrfs/volumes.c:3678 [inline]\n reset_balance_state+0x25e/0x3c0 fs/btrfs/volumes.c:3742\n btrfs_balance+0xead/0x10c0 fs/btrfs/volumes.c:4574\n btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3673\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:907 [inline]\n __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n[CAUSE]\nThe allocation failure happens at the start_transaction() inside\nprepare_to_relocate(), and during the error handling we call\nunset_reloc_control(), which makes fs_info->balance_ctl to be NULL.\n\nThen we continue the error path cleanup in btrfs_balance() by calling\nreset_balance_state() which will call del_balance_item() to fully delete\nthe balance item in the root tree.\n\nHowever during the small window between set_reloc_contrl() and\nunset_reloc_control(), we can have a subvolume tree update and created a\nreloc_root for that subvolume.\n\nThen we go into the final btrfs_commit_transaction() of\ndel_balance_item(), and into btrfs_update_reloc_root() inside\ncommit_fs_roots().\n\nThat function checks if fs_info->reloc_ctl is in the merge_reloc_tree\nstage, but since fs_info->reloc_ctl is NULL, it results a NULL pointer\ndereference.\n\n[FIX]\nJust add extra check on fs_info->reloc_ctl inside\nbtrfs_update_reloc_root(), before checking\nfs_info->reloc_ctl->merge_reloc_tree.\n\nThat DEAD_RELOC_TREE handling is to prevent further modification to the\nreloc tree during merge stage, but since there is no reloc_ctl at all,\nwe do not need to bother that.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "3fd0a5585eb98e074fb9934549c8d85c49756c0d", "status": "affected", "versionType": "git", "lessThan": "1282f001cbf56e5dd6e90a18e205a566793f4be0" }, { "version": "3fd0a5585eb98e074fb9934549c8d85c49756c0d", "status": "affected", "versionType": "git", "lessThan": "d73d48acf36f57362df7e4f9d76568168bf5e944" }, { "version": "3fd0a5585eb98e074fb9934549c8d85c49756c0d", "status": "affected", "versionType": "git", "lessThan": "37fee9c220b92c3b7bf22b51c51dde5364e7590b" }, { "version": "3fd0a5585eb98e074fb9934549c8d85c49756c0d", "status": "affected", "versionType": "git", "lessThan": "d13249c0df7aab885acb149695f82c54c0822a70" }, { "version": "3fd0a5585eb98e074fb9934549c8d85c49756c0d", "status": "affected", "versionType": "git", "lessThan": "7ad0c5868f2f0418619089513d95230c66cb7eb4" }, { "version": "3fd0a5585eb98e074fb9934549c8d85c49756c0d", "status": "affected", "versionType": "git", "lessThan": "dc02c1440705e3451abd1c2c8114a5c1bb188e9f" }, { "version": "3fd0a5585eb98e074fb9934549c8d85c49756c0d", "status": "affected", "versionType": "git", "lessThan": "39356ec0e319ed07627b3a0f402d0608546509e6" }, { "version": "3fd0a5585eb98e074fb9934549c8d85c49756c0d", "status": "affected", "versionType": "git", "lessThan": "c3b47f49e83197e8dffd023ec568403bcdbb774b" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "2.6.35", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "2.6.35" }, { "version": "5.4.285", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.4.*" }, { "version": "5.10.227", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.168", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.113", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.55", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.10.14", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.10.*" }, { "version": "6.11.3", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.11.*" }, { "version": "6.12", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }