{"cve":"CVE-2024-26956","nvd":{"published":"2024-05-01T06:15:11.837","modified":"2026-06-17T07:18:47.107","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: fix failure to detect DAT corruption in btree and direct mappings\n\nPatch series \"nilfs2: fix kernel bug at submit_bh_wbc()\".\n\nThis resolves a kernel BUG reported by syzbot.  Since there are two\nflaws involved, I've made each one a separate patch.\n\nThe first patch alone resolves the syzbot-reported bug, but I think\nboth fixes should be sent to stable, so I've tagged them as such.\n\n\nThis patch (of 2):\n\nSyzbot has reported a kernel bug in submit_bh_wbc() when writing file data\nto a nilfs2 file system whose metadata is corrupted.\n\nThere are two flaws involved in this issue.\n\nThe first flaw is that when nilfs_get_block() locates a data block using\nbtree or direct mapping, if the disk address translation routine\nnilfs_dat_translate() fails with internal code -ENOENT due to DAT metadata\ncorruption, it can be passed back to nilfs_get_block().  This causes\nnilfs_get_block() to misidentify an existing block as non-existent,\ncausing both data block lookup and insertion to fail inconsistently.\n\nThe second flaw is that nilfs_get_block() returns a successful status in\nthis inconsistent state.  This causes the caller __block_write_begin_int()\nor others to request a read even though the buffer is not mapped,\nresulting in a BUG_ON check for the BH_Mapped flag in submit_bh_wbc()\nfailing.\n\nThis fixes the first issue by changing the return value to code -EINVAL\nwhen a conversion using DAT fails with code -ENOENT, avoiding the\nconflicting condition that leads to the kernel bug described above.  Here,\ncode -EINVAL indicates that metadata corruption was detected during the\nblock lookup, which will be properly handled as a file system error and\nconverted to -EIO when passing through the nilfs2 bmap layer.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/2e2619ff5d0def4bb6c2037a32a6eaa28dd95c84","https://git.kernel.org/stable/c/46b832e09d43b394ac0f6d9485d2b1a06593f0b7","https://git.kernel.org/stable/c/82827ca21e7c8a91384c5baa656f78a5adfa4ab4","https://git.kernel.org/stable/c/9cbe1ad5f4354f4df1445e5f4883983328cd6d8e","https://git.kernel.org/stable/c/a8e4d098de1c0f4c5c1f2ed4633a860f0da6d713"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:49:08.435428910+00:00"},"epss":{"cve":"CVE-2024-26956","score":0.00255,"percentile":0.17199,"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."]}