{"id":"CVE-2026-97416","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()\n\n[BUG]\nRunning btrfs balance can trigger a null-ptr-deref before relocating a\ndata chunk…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()\n\n[BUG]\nRunning btrfs balance can trigger a null-ptr-deref before relocating a\ndata chunk…","severity":"medium","vendor":"Linux","product":"Linux","affected":["Linux >= a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 < 9f37a6d6ae9e998232e2ba091ab4999cdf967e1b","Linux >= a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 < e479236a8f4d85c4fb6b3f7c2556c21f583e2bf2","Linux >= a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 < 322f891b4d4fe64acb3351a0ffa62a7fa5ba7256","Linux >= a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 < 81a664ed8b1a44c76b204c4bd0d751317a02c5cd","Linux >= a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 < 9740dd0c17a4be8cc47a06c5ca5293471a7e286e","Linux >= a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 < 59f75e0c8724d4adebc08c7dd3ff2358b80c21f7","Linux >= a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 < 18d32b0013efba19f7ad3e5b08d7aee813d604a6","Linux 4.16"],"published":"2026-09-24","updated":"2026-10-03","sourceUpdated":"2026-10-03T11:17:53.617","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97416","references":[{"url":"https://git.kernel.org/stable/c/18d32b0013efba19f7ad3e5b08d7aee813d604a6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/322f891b4d4fe64acb3351a0ffa62a7fa5ba7256","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/59f75e0c8724d4adebc08c7dd3ff2358b80c21f7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/81a664ed8b1a44c76b204c4bd0d751317a02c5cd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9740dd0c17a4be8cc47a06c5ca5293471a7e286e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9f37a6d6ae9e998232e2ba091ab4999cdf967e1b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e479236a8f4d85c4fb6b3f7c2556c21f583e2bf2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97416.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-97416"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2540566"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-97416"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97416"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97416.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00173,"epssPercentile":0.06644,"ingestedAt":"2026-09-24T16:47:15.885Z","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-476"],"slug":"CVE-2026-97416","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()\n\n[BUG]\nRunning btrfs balance can trigger a null-ptr-deref before relocating a\ndata chunk when metadata corruption leaves a chunk in the chunk tree\nwithout a corresponding block group in the in-memory cache:\n\n  KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]\n  RIP: 0010:btrfs_may_alloc_data_chunk+0x40/0x1c0 fs/btrfs/volumes.c:3601\n  Call Trace:\n    __btrfs_balance fs/btrfs/volumes.c:4217 [inline]\n    btrfs_balance+0x2516/0x42b0 fs/btrfs/volumes.c:4604\n    btrfs_ioctl_balance fs/btrfs/ioctl.c:3577 [inline]\n    btrfs_ioctl+0x25cf/0x5b90 fs/btrfs/ioctl.c:5313\n    ...\n\n[CAUSE]\n__btrfs_balance() iterates the on-disk chunk tree and passes the chunk\nlogical bytenr to btrfs_may_alloc_data_chunk() before relocating a data\nchunk. That helper then queries the in-memory block group cache:\n\n  cache = btrfs_lookup_block_group(fs_info, chunk_offset);\n  chunk_type = cache->flags;   /* cache may be NULL */\n\nA corrupt image can contain a chunk item whose matching block group\nitem is missing, so no block group is ever inserted into the cache. In\nthat case btrfs_lookup_block_group() returns NULL.\n\nThe code only guards this with ASSERT(cache), which becomes a no-op when\nCONFIG_BTRFS_ASSERT is disabled. The subsequent dereference of\ncache->flags therefore crashes the kernel.\n\n[FIX]\nAdd a NULL check after btrfs_lookup_block_group() in\nbtrfs_may_alloc_data_chunk() and print and error message for clarity.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10 · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97416.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224197,"id":"CVE-2026-97416","ts":1792325009665,"field":"cvss","old":null,"new":"5.5"},{"seq":224196,"id":"CVE-2026-97416","ts":1792325009665,"field":"severity","old":"none","new":"medium"}]}