{"id":"CVE-2026-53064","summary":"dm cache: fix null-deref with concurrent writes in passthrough mode","details":"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-\u003ecell 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\u003csnip\u003e\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\u003csnip\u003e\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-\u003ecell is valid before attempting to unlock it.","modified":"2026-07-16T03:31:07.921796464Z","published":"2026-06-24T16:30:07.536Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53064.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/01264a6a3a3ad7ac1d73443299cd5a9568002454"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0aa745fea1f8dc81bcdd0a45e215b6706727b482"},{"type":"WEB","url":"https://git.kernel.org/stable/c/25dcc1989c194ba2b5fb6d03cbb9b83814ac0d15"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7d1f98d668ee34c1d15bdc0420fdd062f24a27c0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a2635d541a93fd111e743cf14b6275dc81be2abc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c7fb6bc864c4910b344dafa36dd5028e9b980768"},{"type":"WEB","url":"https://git.kernel.org/stable/c/df3b8ef06cc62de4fca5d2108e285085b3cffd44"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ee38fb00e1a80f46a4990e38f25ecb04ae7b7417"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53064.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53064"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"b29d4986d0da1a27cd35917cdb433672f5c95d7f"},{"fixed":"01264a6a3a3ad7ac1d73443299cd5a9568002454"},{"fixed":"ee38fb00e1a80f46a4990e38f25ecb04ae7b7417"},{"fixed":"c7fb6bc864c4910b344dafa36dd5028e9b980768"},{"fixed":"0aa745fea1f8dc81bcdd0a45e215b6706727b482"},{"fixed":"a2635d541a93fd111e743cf14b6275dc81be2abc"},{"fixed":"25dcc1989c194ba2b5fb6d03cbb9b83814ac0d15"},{"fixed":"df3b8ef06cc62de4fca5d2108e285085b3cffd44"},{"fixed":"7d1f98d668ee34c1d15bdc0420fdd062f24a27c0"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53064.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.12.0"},{"fixed":"5.10.258"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.209"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.141"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.91"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.33"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53064.json"}}],"schema_version":"1.7.5"}