{"cve":"CVE-2022-49708","nvd":{"published":"2025-02-26T07:01:46.607","modified":"2026-06-17T05:18:55.683","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix bug_on ext4_mb_use_inode_pa\n\nHulk Robot reported a BUG_ON:\n==================================================================\nkernel BUG at fs/ext4/mballoc.c:3211!\n[...]\nRIP: 0010:ext4_mb_mark_diskspace_used.cold+0x85/0x136f\n[...]\nCall Trace:\n ext4_mb_new_blocks+0x9df/0x5d30\n ext4_ext_map_blocks+0x1803/0x4d80\n ext4_map_blocks+0x3a4/0x1a10\n ext4_writepages+0x126d/0x2c30\n do_writepages+0x7f/0x1b0\n __filemap_fdatawrite_range+0x285/0x3b0\n file_write_and_wait_range+0xb1/0x140\n ext4_sync_file+0x1aa/0xca0\n vfs_fsync_range+0xfb/0x260\n do_fsync+0x48/0xa0\n[...]\n==================================================================\n\nAbove issue may happen as follows:\n-------------------------------------\ndo_fsync\n vfs_fsync_range\n  ext4_sync_file\n   file_write_and_wait_range\n    __filemap_fdatawrite_range\n     do_writepages\n      ext4_writepages\n       mpage_map_and_submit_extent\n        mpage_map_one_extent\n         ext4_map_blocks\n          ext4_mb_new_blocks\n           ext4_mb_normalize_request\n            >>> start + size <= ac->ac_o_ex.fe_logical\n           ext4_mb_regular_allocator\n            ext4_mb_simple_scan_group\n             ext4_mb_use_best_found\n              ext4_mb_new_preallocation\n               ext4_mb_new_inode_pa\n                ext4_mb_use_inode_pa\n                 >>> set ac->ac_b_ex.fe_len <= 0\n           ext4_mb_mark_diskspace_used\n            >>> BUG_ON(ac->ac_b_ex.fe_len <= 0);\n\nwe can easily reproduce this problem with the following commands:\n\t`fallocate -l100M disk`\n\t`mkfs.ext4 -b 1024 -g 256 disk`\n\t`mount disk /mnt`\n\t`fsstress -d /mnt -l 0 -n 1000 -p 1`\n\nThe size must be smaller than or equal to EXT4_BLOCKS_PER_GROUP.\nTherefore, \"start + size <= ac->ac_o_ex.fe_logical\" may occur\nwhen the size is truncated. So start should be the start position of\nthe group where ac_o_ex.fe_logical is located after alignment.\nIn addition, when the value of fe_logical or EXT4_BLOCKS_PER_GROUP\nis very large, the value calculated by start_off is more accurate.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-617"],"references":["https://git.kernel.org/stable/c/5707d721d1819db57dba57b1d4623034fcb32047","https://git.kernel.org/stable/c/6880fb2e64331b9fdc85d3f32b1d7e81ad8703f1","https://git.kernel.org/stable/c/6fdaf31ad5f3d3afab744dfd9a8b0d9142aa881f","https://git.kernel.org/stable/c/887a3e9ad4b8309a2266bce7ae749b2bf1f7a687","https://git.kernel.org/stable/c/90f0f9d45dff0128c0fca0d2358c4153b024afa6"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:59:48.811064707+00:00"},"epss":{"cve":"CVE-2022-49708","score":0.00284,"percentile":0.20993,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}