{"id":"CVE-2025-40119","summary":"ext4: fix potential null deref in ext4_mb_init()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix potential null deref in ext4_mb_init()\n\nIn ext4_mb_init(), ext4_mb_avg_fragment_size_destroy() may be called\nwhen sbi-\u003es_mb_avg_fragment_size remains uninitialized (e.g., if groupinfo\nslab cache allocation fails). Since ext4_mb_avg_fragment_size_destroy()\nlacks null pointer checking, this leads to a null pointer dereference.\n\n==================================================================\nEXT4-fs: no memory for groupinfo slab cache\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nPGD 0 P4D 0\nOops: Oops: 0002 [#1] SMP PTI\nCPU:2 UID: 0 PID: 87 Comm:mount Not tainted 6.17.0-rc2 #1134 PREEMPT(none)\nRIP: 0010:_raw_spin_lock_irqsave+0x1b/0x40\nCall Trace:\n \u003cTASK\u003e\n xa_destroy+0x61/0x130\n ext4_mb_init+0x483/0x540\n __ext4_fill_super+0x116d/0x17b0\n ext4_fill_super+0xd3/0x280\n get_tree_bdev_flags+0x132/0x1d0\n vfs_get_tree+0x29/0xd0\n do_new_mount+0x197/0x300\n __x64_sys_mount+0x116/0x150\n do_syscall_64+0x50/0x1c0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n==================================================================\n\nTherefore, add necessary null check to ext4_mb_avg_fragment_size_destroy()\nto prevent this issue. The same fix is also applied to\next4_mb_largest_free_orders_destroy().","modified":"2026-04-02T12:48:17.439940Z","published":"2025-11-12T10:23:18.449Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40119.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/00110f3cfc9b34b2dfee2a6c9e55a0ae6df125ae"},{"type":"WEB","url":"https://git.kernel.org/stable/c/08d9175578d6a8e9b81921898fbf01aa669cd2be"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3c3fac6bc0a9c00dbe65d8dc0d3a282afe4d3188"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40119.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40119"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d99d714f714c9492dc64d8ab4329b083dbfa9cab"},{"fixed":"08d9175578d6a8e9b81921898fbf01aa669cd2be"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f7eaacbb4e54f8a6c6674c16eff54f703ea63d5e"},{"fixed":"00110f3cfc9b34b2dfee2a6c9e55a0ae6df125ae"},{"fixed":"3c3fac6bc0a9c00dbe65d8dc0d3a282afe4d3188"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40119.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.17.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-40119.json"}}],"schema_version":"1.7.5"}