{"cve":"CVE-2024-50279","nvd":{"published":"2024-11-19T02:16:30.210","modified":"2026-06-17T08:04:05.377","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache: fix out-of-bounds access to the dirty bitset when resizing\n\ndm-cache checks the dirty bits of the cache blocks to be dropped when\nshrinking the fast device, but an index bug in bitset iteration causes\nout-of-bounds access.\n\nReproduce steps:\n\n1. create a cache device of 1024 cache blocks (128 bytes dirty bitset)\n\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ndmsetup create cdata --table \"0 131072 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\ndmsetup create cache --table \"0 524288 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\n\n2. shrink the fast device to 512 cache blocks, triggering out-of-bounds\n   access to the dirty bitset (offset 0x80)\n\ndmsetup suspend cache\ndmsetup reload cdata --table \"0 65536 linear /dev/sdc 8192\"\ndmsetup resume cdata\ndmsetup resume cache\n\nKASAN reports:\n\n  BUG: KASAN: vmalloc-out-of-bounds in cache_preresume+0x269/0x7b0\n  Read of size 8 at addr ffffc900000f3080 by task dmsetup/131\n\n  (...snip...)\n  The buggy address belongs to the virtual mapping at\n   [ffffc900000f3000, ffffc900000f5000) created by:\n   cache_ctr+0x176a/0x35f0\n\n  (...snip...)\n  Memory state around the buggy address:\n   ffffc900000f2f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n   ffffc900000f3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n  >ffffc900000f3080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n                     ^\n   ffffc900000f3100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n   ffffc900000f3180: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n\nFix by making the index post-incremented.","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/3b02c40ff10fdf83cc545850db208de855ebe22c","https://git.kernel.org/stable/c/4fa4feb873cea0e9d6ff883b37cca6f33169d8b4","https://git.kernel.org/stable/c/56507203e1b6127967ec2b51fb0b23a0d4af1334","https://git.kernel.org/stable/c/792227719725497ce10a8039803bec13f89f8910","https://git.kernel.org/stable/c/8501e38dc9e0060814c4085815fc83da3e6d43bf"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:57:34.731061660+00:00"},"epss":{"cve":"CVE-2024-50279","score":0.00262,"percentile":0.18077,"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."]}