{"cve":"CVE-2024-50278","nvd":{"published":"2024-11-19T02:16:30.113","modified":"2026-06-17T08:04:05.180","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache: fix potential out-of-bounds access on the first resume\n\nOut-of-bounds access occurs if the fast device is expanded unexpectedly\nbefore the first-time resume of the cache table. This happens because\nexpanding the fast device requires reloading the cache table for\ncache_create to allocate new in-core data structures that fit the new\nsize, and the check in cache_preresume is not performed during the\nfirst resume, leading to the issue.\n\nReproduce steps:\n\n1. prepare component devices:\n\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ndmsetup create cdata --table \"0 65536 linear /dev/sdc 8192\"\ndmsetup create corig --table \"0 524288 linear /dev/sdc 262144\"\ndd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct\n\n2. load a cache table of 512 cache blocks, and deliberately expand the\n   fast device before resuming the cache, making the in-core data\n   structures inadequate.\n\ndmsetup create cache --notable\ndmsetup reload cache --table \"0 524288 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\ndmsetup reload cdata --table \"0 131072 linear /dev/sdc 8192\"\ndmsetup resume cdata\ndmsetup resume cache\n\n3. suspend the cache to write out the in-core dirty bitset and hint\n   array, leading to out-of-bounds access to the dirty bitset at offset\n   0x40:\n\ndmsetup suspend cache\n\nKASAN reports:\n\n  BUG: KASAN: vmalloc-out-of-bounds in is_dirty_callback+0x2b/0x80\n  Read of size 8 at addr ffffc90000085040 by task dmsetup/90\n\n  (...snip...)\n  The buggy address belongs to the virtual mapping at\n   [ffffc90000085000, ffffc90000087000) created by:\n   cache_ctr+0x176a/0x35f0\n\n  (...snip...)\n  Memory state around the buggy address:\n   ffffc90000084f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n   ffffc90000084f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n  >ffffc90000085000: 00 00 00 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8\n                                             ^\n   ffffc90000085080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n   ffffc90000085100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n\nFix by checking the size change on the first resume.","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:N/A:H","score":7.1},"cwes":["CWE-125"],"references":["https://git.kernel.org/stable/c/036dd6e3d2638103e0092864577ea1d091466b86","https://git.kernel.org/stable/c/13ed3624c6ef283acefa4cc42cc8ae54fd4391a4","https://git.kernel.org/stable/c/2222b0929d00e2d13732b799b63be391b5de4492","https://git.kernel.org/stable/c/483b7261b35a9d369082ab298a6670912243f0be","https://git.kernel.org/stable/c/c0ade5d98979585d4f5a93e4514c2e9a65afa08d"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:57:34.731061660+00:00"},"epss":{"cve":"CVE-2024-50278","score":0.00262,"percentile":0.18072,"date":"2026-11-01"},"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."]}