{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-90186", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-90186", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-09-17T16:07:09.047Z", "updatedAt": "2026-10-19T08:59:23.057Z", "importedAt": "2026-10-24T01:58:35.090Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "null_blk: reject per-device queue resize for shared tag set", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: reject per-device queue resize for shared tag set\n\nWhen shared_tags is enabled, null_setup_tagset() makes the device use the\nglobal tag_set, whose driver_data stays NULL. null_map_queues() therefore\nfalls back to the module-wide g_submit_queues/g_poll_queues instead of any\nper-device value.\n\nResizing submit_queues or poll_queues via configfs on such a device calls\nblk_mq_update_nr_hw_queues() on the shared set, shrinking\nset->nr_hw_queues. __blk_mq_realloc_hw_ctxs() only grows the\nq->queue_hw_ctx[] allocation, so on shrink it merely exits and NULLs the\nnow-excess hctx slots. null_map_queues(), however, keeps mapping CPUs with\nthe unchanged g_submit_queues/g_poll_queues, so mq_map[] ends up pointing\nat those NULLed hctx slots. blk_mq_map_swqueue() then dereferences the NULL\nhctx (hctx->cpumask), crashing the kernel:\n\n[ 460.218374] KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]\n[ 460.219003] CPU: 24 UID: 0 PID: 1492 Comm: sh Not tainted 7.2.0-rc2+ #67 PREEMPT(full)\n[ 460.219792] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014\n[ 460.220452] RIP: 0010:blk_mq_map_swqueue+0x4db/0x1430\n......\n[ 460.228977] Call Trace:\n[ 460.229175] \n[ 460.229354] blk_mq_update_nr_hw_queues+0xd49/0x11c0\n[ 460.229779] ? __pfx_blk_mq_update_nr_hw_queues+0x10/0x10\n[ 460.230200] nullb_update_nr_hw_queues+0x1a9/0x370 [null_blk]\n[ 460.230694] nullb_device_submit_queues_store+0xd9/0x170 [null_blk]\n[ 460.231190] ? __pfx_nullb_device_submit_queues_store+0x10/0x10 [null_blk]\n[ 460.231776] ? configfs_write_iter+0x35c/0x4e0\n[ 460.232122] configfs_write_iter+0x286/0x4e0\n[ 460.232460] vfs_write+0x52d/0xd00\n[ 460.232779] ? __x64_sys_openat+0x108/0x1d0\n[ 460.233106] ? __pfx_vfs_write+0x10/0x10\n[ 460.233413] ? fdget_pos+0x1cf/0x4c0\n[ 460.233745] ? fput_close+0x133/0x190\n[ 460.234038] ? __pfx_expand_files+0x10/0x10\n[ 460.234368] ksys_write+0xfc/0x1d0\n\nReproducer:\nmodprobe null_blk shared_tags=1 submit_queues=64 poll_queues=1\nmkdir /sys/kernel/config/nullb/dev\necho 1 > /sys/kernel/config/nullb/dev/power\necho 1 > /sys/kernel/config/nullb/dev/submit_queues\n\nA per-device resize of a shared tag set is meaningless anyway, so reject it\nwith -EINVAL in nullb_update_nr_hw_queues() when the device is bound to the\nglobal tag_set.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3", "status": "affected", "versionType": "git", "lessThan": "9c7bae099ddc92676ad1b7e29dd6c089e5f6196c" }, { "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3", "status": "affected", "versionType": "git", "lessThan": "fcd53f3e8b758c79c3f2420d28a2a1dce6fda61a" }, { "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3", "status": "affected", "versionType": "git", "lessThan": "f609f7bf9ce8c2fc427705c4a9f623a281239d06" }, { "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3", "status": "affected", "versionType": "git", "lessThan": "3e35ad503386a2e8a0e0460530dcbf421c79f6f2" }, { "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3", "status": "affected", "versionType": "git", "lessThan": "baff300541a0012907cdde349728739fe16176d7" }, { "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3", "status": "affected", "versionType": "git", "lessThan": "1cdfe2fa62b48728a9b436fbbd3dbe4c11593e24" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.5", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.5" }, { "version": "6.1.188", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.157", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.110", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.52", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.2.6", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.2.*" }, { "version": "7.3", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }