{"api_version":"1","generated_at":"2026-06-04T00:44:09+00:00","cve":"CVE-2025-68823","urls":{"html":"https://cve.report/CVE-2025-68823","api":"https://cve.report/api/cve/CVE-2025-68823.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2025-68823","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-68823"},"summary":{"title":"ublk: fix deadlock when reading partition table","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix deadlock when reading partition table\n\nWhen one process(such as udev) opens ublk block device (e.g., to read\nthe partition table via bdev_open()), a deadlock[1] can occur:\n\n1. bdev_open() grabs disk->open_mutex\n2. The process issues read I/O to ublk backend to read partition table\n3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()\n   runs bio->bi_end_io() callbacks\n4. If this triggers fput() on file descriptor of ublk block device, the\n   work may be deferred to current task's task work (see fput() implementation)\n5. This eventually calls blkdev_release() from the same context\n6. blkdev_release() tries to grab disk->open_mutex again\n7. Deadlock: same task waiting for a mutex it already holds\n\nThe fix is to run blk_update_request() and blk_mq_end_request() with bottom\nhalves disabled. This forces blkdev_release() to run in kernel work-queue\ncontext instead of current task work context, and allows ublk server to make\nforward progress, and avoids the deadlock.\n\n[axboe: rewrite comment in ublk]","state":"PUBLISHED","assigner":"Linux","published_at":"2026-01-13 16:16:04","updated_at":"2026-06-01 17:16:38"},"problem_types":["CWE-667"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","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","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://git.kernel.org/stable/c/c258f5c4502c9667bccf5d76fa731ab9c96687c1","name":"https://git.kernel.org/stable/c/c258f5c4502c9667bccf5d76fa731ab9c96687c1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0460e09a614291f06c008443f47393c37b7358e7","name":"https://git.kernel.org/stable/c/0460e09a614291f06c008443f47393c37b7358e7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9bcc47343ee0ef346aa7b2b460c8ff56bd882fe7","name":"https://git.kernel.org/stable/c/9bcc47343ee0ef346aa7b2b460c8ff56bd882fe7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/64c0b7e2293757e8320f13434cd809f1c9257a62","name":"https://git.kernel.org/stable/c/64c0b7e2293757e8320f13434cd809f1c9257a62","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/27bb79b7717b2fbb111a1c13548b2786ee712dca","name":"https://git.kernel.org/stable/c/27bb79b7717b2fbb111a1c13548b2786ee712dca","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-68823","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68823","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 71f28f3136aff5890cd56de78abc673f8393cad9 27bb79b7717b2fbb111a1c13548b2786ee712dca git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 71f28f3136aff5890cd56de78abc673f8393cad9 64c0b7e2293757e8320f13434cd809f1c9257a62 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 71f28f3136aff5890cd56de78abc673f8393cad9 9bcc47343ee0ef346aa7b2b460c8ff56bd882fe7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 71f28f3136aff5890cd56de78abc673f8393cad9 0460e09a614291f06c008443f47393c37b7358e7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix deadlock when reading partition table\n\nWhen one process(such as udev) opens ublk block device (e.g., to read\nthe partition table via bdev_open()), a deadlock[1] can occur:\n\n1. bdev_open() grabs disk->open_mutex\n2. The process issues read I/O to ublk backend to read partition table\n3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()\n   runs bio->bi_end_io() callbacks\n4. If this triggers fput() on file descriptor of ublk block device, the\n   work may be deferred to current task's task work (see fput() implementation)\n5. This eventually calls blkdev_release() from the same context\n6. blkdev_release() tries to grab disk->open_mutex again\n7. Deadlock: same task waiting for a mutex it already holds\n\nThe fix is to run blk_update_request() and blk_mq_end_request() with bottom\nhalves disabled. This forces blkdev_release() to run in kernel work-queue\ncontext instead of current task work context, and allows ublk server to make\nforward progress, and avoids the deadlock.\n\n[axboe: rewrite comment in ublk]"}],"providerMetadata":{"dateUpdated":"2026-06-01T16:05:45.871Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/27bb79b7717b2fbb111a1c13548b2786ee712dca"},{"url":"https://git.kernel.org/stable/c/64c0b7e2293757e8320f13434cd809f1c9257a62"},{"url":"https://git.kernel.org/stable/c/9bcc47343ee0ef346aa7b2b460c8ff56bd882fe7"},{"url":"https://git.kernel.org/stable/c/0460e09a614291f06c008443f47393c37b7358e7"},{"url":"https://git.kernel.org/stable/c/c258f5c4502c9667bccf5d76fa731ab9c96687c1"}],"title":"ublk: fix deadlock when reading partition table","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2025-68823","datePublished":"2026-01-13T15:29:25.392Z","dateReserved":"2025-12-24T10:30:51.048Z","dateUpdated":"2026-06-01T16:05:45.871Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-01-13 16:16:04","lastModifiedDate":"2026-06-01 17:16:38","problem_types":["CWE-667"],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0","versionEndExcluding":"6.6.124","matchCriteriaId":"07A21134-3555-4ED3-8B0A-940F93C45530"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.70","matchCriteriaId":"F3791390-0628-4808-99EF-1ED8ABF60933"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.3","matchCriteriaId":"2DC484D8-FB4F-4112-900F-AE333B6FE7A7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*","matchCriteriaId":"17B67AA7-40D6-4AFA-8459-F200F3D7CFD1"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2025","CveId":"68823","Ordinal":"1","Title":"ublk: fix deadlock when reading partition table","CVE":"CVE-2025-68823","Year":"2025"},"notes":[{"CveYear":"2025","CveId":"68823","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix deadlock when reading partition table\n\nWhen one process(such as udev) opens ublk block device (e.g., to read\nthe partition table via bdev_open()), a deadlock[1] can occur:\n\n1. bdev_open() grabs disk->open_mutex\n2. The process issues read I/O to ublk backend to read partition table\n3. In __ublk_complete_rq(), blk_update_request() or blk_mq_end_request()\n   runs bio->bi_end_io() callbacks\n4. If this triggers fput() on file descriptor of ublk block device, the\n   work may be deferred to current task's task work (see fput() implementation)\n5. This eventually calls blkdev_release() from the same context\n6. blkdev_release() tries to grab disk->open_mutex again\n7. Deadlock: same task waiting for a mutex it already holds\n\nThe fix is to run blk_update_request() and blk_mq_end_request() with bottom\nhalves disabled. This forces blkdev_release() to run in kernel work-queue\ncontext instead of current task work context, and allows ublk server to make\nforward progress, and avoids the deadlock.\n\n[axboe: rewrite comment in ublk]","Type":"Description","Title":"ublk: fix deadlock when reading partition table"}]}}}