{"id":"CVE-2026-53064","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-53064","generatedAt":"2026-10-28T03:41:49.291Z","title":"In the Linux kernel, the following vulnerability has been resolved: dm cache: fix null-deref with concurrent writes in passthrough mode In passthrough mode, when dm-cache starts to invalidate a cache entry and bio prison cell lock fails due to…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache: fix null-deref with concurrent writes in passthrough mode\n\nIn passthrough mode, when dm-cache starts to invalidate a cache\nentry and bio prison cell lock fails due to concurrent write to\nthe same cached block, mg->cell remains NULL. The error path in\ninvalidate_complete() attempts to unlock and free the cell\nunconditionally, causing a NULL pointer dereference:\n\nKASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\nCPU: 0 UID: 0 PID: 134 Comm: fio Not tainted 6.19.0-rc7 #3 PREEMPT\nRIP: 0010:dm_cell_unlock_v2+0x3f/0x210\n<snip>\nCall Trace:\n invalidate_complete+0xef/0x430\n map_bio+0x130f/0x1a10\n cache_map+0x320/0x6b0\n __map_bio+0x458/0x510\n dm_submit_bio+0x40e/0x16d0\n __submit_bio+0x419/0x870\n<snip>\n\nReproduce steps:\n\n1. Create a cache device\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 262144 linear /dev/sdc 262144\"\ndd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct\ndmsetup create cache --table \"0 262144 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\n\n2. Promote the first data block into cache\n\nfio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k \\\n--direct=1 --size=64k\n\n3. Reload the cache into passthrough mode\n\ndmsetup suspend cache\ndmsetup reload cache --table \"0 262144 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0\"\ndmsetup resume cache\n\n4. Write to the first cached block concurrently\n\nfio --filename=/dev/mapper/cache --name test --rw=randwrite --bs=4k \\\n--randrepeat=0 --direct=1 --numjobs=2 --size 64k\n\nFix by checking if mg->cell is valid before attempting to unlock it.","published":"2026-06-24T17:17:19.000Z","lastModified":"2026-07-21T17:36:30.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-476"],"affected":["linux/linux kernel"],"epss":{"score":0.00123,"percentile":0.02,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.12%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/01264a6a3a3ad7ac1d73443299cd5a9568002454","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/0aa745fea1f8dc81bcdd0a45e215b6706727b482","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/25dcc1989c194ba2b5fb6d03cbb9b83814ac0d15","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7d1f98d668ee34c1d15bdc0420fdd062f24a27c0","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a2635d541a93fd111e743cf14b6275dc81be2abc","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c7fb6bc864c4910b344dafa36dd5028e9b980768","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/df3b8ef06cc62de4fca5d2108e285085b3cffd44","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ee38fb00e1a80f46a4990e38f25ecb04ae7b7417","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53064","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}