CVE-2023-53531

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2023-53531", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-10-01T11:39:39.408Z", "datePublished": "2025-10-01T11:46:15.949Z", "dateUpdated": "2026-08-05T09:14:38.269Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:14:38.269Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: fix poll request timeout handling\n\nWhen doing io_uring benchmark on /dev/nullb0, it's easy to crash the\nkernel if poll requests timeout triggered, as reported by David. [1]\n\nBUG: kernel NULL pointer dereference, address: 0000000000000008\nWorkqueue: kblockd blk_mq_timeout_work\nRIP: 0010:null_timeout_rq+0x4e/0x91\nCall Trace:\n ? null_timeout_rq+0x4e/0x91\n blk_mq_handle_expired+0x31/0x4b\n bt_iter+0x68/0x84\n ? bt_tags_iter+0x81/0x81\n __sbitmap_for_each_set.constprop.0+0xb0/0xf2\n ? __blk_mq_complete_request_remote+0xf/0xf\n bt_for_each+0x46/0x64\n ? __blk_mq_complete_request_remote+0xf/0xf\n ? percpu_ref_get_many+0xc/0x2a\n blk_mq_queue_tag_busy_iter+0x14d/0x18e\n blk_mq_timeout_work+0x95/0x127\n process_one_work+0x185/0x263\n worker_thread+0x1b5/0x227\n\nThis is indeed a race problem between null_timeout_rq() and null_poll().\n\nnull_poll()\t\t\t\tnull_timeout_rq()\n spin_lock(&nq->poll_lock)\n list_splice_init(&nq->poll_list, &list)\n spin_unlock(&nq->poll_lock)\n\n while (!list_empty(&list))\n req = list_first_entry()\n list_del_init()\n ...\n blk_mq_add_to_batch()\n // req->rq_next = NULL\n\t\t\t\t\tspin_lock(&nq->poll_lock)\n\n\t\t\t\t\t// rq->queuelist->next == NULL\n\t\t\t\t\tlist_del_init(&rq->queuelist)\n\n\t\t\t\t\tspin_unlock(&nq->poll_lock)\n\nFix these problems by setting requests state to MQ_RQ_COMPLETE under\nnq->poll_lock protection, in which null_timeout_rq() can safely detect\nthis race and early return.\n\nNote this patch just fix the kernel panic when request timeout happen.\n\n[1] https://lore.kernel.org/all/3893581.1691785261@warthog.procyon.org.uk/"}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - Exploitation requires opening the local block device /dev/nullb0 and issuing polled direct I/O (io_uring IOPOLL or preadv2 RWF_HIPRI); there is no remote or adjacent-network path into null_blk.\nAC:L - The attacker controls both sides of the race \u2014 it submits the polled requests, controls when it calls into null_poll(), and the 5-second timeout is fixed unconditionally by null_add_dev() (tag_set->timeout = 5 * HZ), so the collision with blk_mq_timeout_work can be arranged deterministically and retried; the fix author notes it is \"easy to crash the kernel.\"\nPR:L - The vulnerable path contains no capability or namespace check \u2014 any local user able to open the null_blk device node (group disk, benchmarking/CI accounts, or a container handed the device) can reach null_queue_rq/null_poll with ordinary O_DIRECT reads.\nUI:N - The attacker performs the submissions and polling itself; no victim action is required to trigger the race.\nS:U - The corruption is confined to kernel block-layer structures within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Beyond the NULL case, list_del_init() writes &rq->queuelist into the io_comp_batch chain, so blk_mq_end_request_batch() dereferences a bogus struct request and bio pointers, and the double blk_mq_complete_request() frees the tag twice yielding request reuse \u2014 a UAF-class read primitive over kernel heap contents.\nI:H - The race produces doubly-linked-list corruption plus double request completion (tag double-free and reallocation to a concurrent I/O), giving attacker-influenced kernel heap writes exploitable for control-flow hijacking.\nA:H - The documented result is a kernel NULL pointer dereference oops at address 0x8 inside blk_mq_timeout_work on the kblockd workqueue, killing the worker and panicking or wedging the block layer."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/block/null_blk/main.c"], "versions": [{"version": "0a593fbbc245a85940ed34caa3aa1e4cb060c54b", "lessThan": "a0b4a0666beacfe8add9c71d8922475541dbae73", "status": "affected", "versionType": "git"}, {"version": "0a593fbbc245a85940ed34caa3aa1e4cb060c54b", "lessThan": "a7cb2e709f2927cc3c76781df3e45de2381b3b9d", "status": "affected", "versionType": "git"}, {"version": "0a593fbbc245a85940ed34caa3aa1e4cb060c54b", "lessThan": "5a26e45edb4690d58406178b5a9ea4c6dcf2c105", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/block/null_blk/main.c"], "versions": [{"version": "5.16", "status": "affected"}, {"version": "0", "lessThan": "5.16", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.54", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.5.4", "lessThanOrEqual": "6.5.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.1.54"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.5.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/a0b4a0666beacfe8add9c71d8922475541dbae73"}, {"url": "https://git.kernel.org/stable/c/a7cb2e709f2927cc3c76781df3e45de2381b3b9d"}, {"url": "https://git.kernel.org/stable/c/5a26e45edb4690d58406178b5a9ea4c6dcf2c105"}], "title": "null_blk: fix poll request timeout handling", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/block/null_blk/main.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "a0b4a0666beacfe8add9c71d8922475541dbae73", "status": "affected", "version": "0a593fbbc245a85940ed34caa3aa1e4cb060c54b", "versionType": "git"}, {"lessThan": "a7cb2e709f2927cc3c76781df3e45de2381b3b9d", "status": "affected", "version": "0a593fbbc245a85940ed34caa3aa1e4cb060c54b", "versionType": "git"}, {"lessThan": "5a26e45edb4690d58406178b5a9ea4c6dcf2c105", "status": "affected", "version": "0a593fbbc245a85940ed34caa3aa1e4cb060c54b", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/block/null_blk/main.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.16"}, {"lessThan": "5.16", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.54", "versionType": "semver"}, {"lessThanOrEqual": "6.5.*", "status": "unaffected", "version": "6.5.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.6", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "7353B9B4-AFFC-45DE-840E-1A7D2B00E7AD", "versionEndExcluding": "6.1.54", "versionStartIncluding": "5.16", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "CA8C8B88-AF36-445D-A228-AD78F3615373", "versionEndExcluding": "6.5.4", "versionStartIncluding": "6.2", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: fix poll request timeout handling\n\nWhen doing io_uring benchmark on /dev/nullb0, it's easy to crash the\nkernel if poll requests timeout triggered, as reported by David. [1]\n\nBUG: kernel NULL pointer dereference, address: 0000000000000008\nWorkqueue: kblockd blk_mq_timeout_work\nRIP: 0010:null_timeout_rq+0x4e/0x91\nCall Trace:\n ? null_timeout_rq+0x4e/0x91\n blk_mq_handle_expired+0x31/0x4b\n bt_iter+0x68/0x84\n ? bt_tags_iter+0x81/0x81\n __sbitmap_for_each_set.constprop.0+0xb0/0xf2\n ? __blk_mq_complete_request_remote+0xf/0xf\n bt_for_each+0x46/0x64\n ? __blk_mq_complete_request_remote+0xf/0xf\n ? percpu_ref_get_many+0xc/0x2a\n blk_mq_queue_tag_busy_iter+0x14d/0x18e\n blk_mq_timeout_work+0x95/0x127\n process_one_work+0x185/0x263\n worker_thread+0x1b5/0x227\n\nThis is indeed a race problem between null_timeout_rq() and null_poll().\n\nnull_poll()\t\t\t\tnull_timeout_rq()\n spin_lock(&nq->poll_lock)\n list_splice_init(&nq->poll_list, &list)\n spin_unlock(&nq->poll_lock)\n\n while (!list_empty(&list))\n req = list_first_entry()\n list_del_init()\n ...\n blk_mq_add_to_batch()\n // req->rq_next = NULL\n\t\t\t\t\tspin_lock(&nq->poll_lock)\n\n\t\t\t\t\t// rq->queuelist->next == NULL\n\t\t\t\t\tlist_del_init(&rq->queuelist)\n\n\t\t\t\t\tspin_unlock(&nq->poll_lock)\n\nFix these problems by setting requests state to MQ_RQ_COMPLETE under\nnq->poll_lock protection, in which null_timeout_rq() can safely detect\nthis race and early return.\n\nNote this patch just fix the kernel panic when request timeout happen.\n\n[1] https://lore.kernel.org/all/3893581.1691785261@warthog.procyon.org.uk/"}], "id": "CVE-2023-53531", "lastModified": "2026-08-04T10:19:10.767", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 5.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2025-10-01T12:15:57.843", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5a26e45edb4690d58406178b5a9ea4c6dcf2c105"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/a0b4a0666beacfe8add9c71d8922475541dbae73"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/a7cb2e709f2927cc3c76781df3e45de2381b3b9d"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-476"}], "source": "nvd@nist.gov", "type": "Primary"}]}

{"bugzilla": {"description": "kernel: null_blk: fix poll request timeout handling", "id": "2400691", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2400691"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\nnull_blk: fix poll request timeout handling\nWhen doing io_uring benchmark on /dev/nullb0, it's easy to crash the\nkernel if poll requests timeout triggered, as reported by David. [1]\nBUG: kernel NULL pointer dereference, address: 0000000000000008\nWorkqueue: kblockd blk_mq_timeout_work\nRIP: 0010:null_timeout_rq+0x4e/0x91\nCall Trace:\n? null_timeout_rq+0x4e/0x91\nblk_mq_handle_expired+0x31/0x4b\nbt_iter+0x68/0x84\n? bt_tags_iter+0x81/0x81\n__sbitmap_for_each_set.constprop.0+0xb0/0xf2\n? __blk_mq_complete_request_remote+0xf/0xf\nbt_for_each+0x46/0x64\n? __blk_mq_complete_request_remote+0xf/0xf\n? percpu_ref_get_many+0xc/0x2a\nblk_mq_queue_tag_busy_iter+0x14d/0x18e\nblk_mq_timeout_work+0x95/0x127\nprocess_one_work+0x185/0x263\nworker_thread+0x1b5/0x227\nThis is indeed a race problem between null_timeout_rq() and null_poll().\nnull_poll()null_timeout_rq()\nspin_lock(&nq->poll_lock)\nlist_splice_init(&nq->poll_list, &list)\nspin_unlock(&nq->poll_lock)\nwhile (!list_empty(&list))\nreq = list_first_entry()\nlist_del_init()\n...\nblk_mq_add_to_batch()\n// req->rq_next = NULL\nspin_lock(&nq->poll_lock)\n// rq->queuelist->next == NULL\nlist_del_init(&rq->queuelist)\nspin_unlock(&nq->poll_lock)\nFix these problems by setting requests state to MQ_RQ_COMPLETE under\nnq->poll_lock protection, in which null_timeout_rq() can safely detect\nthis race and early return.\nNote this patch just fix the kernel panic when request timeout happen.\n[1] https://lore.kernel.org/all/3893581.1691785261@warthog.procyon.org.uk/"], "name": "CVE-2023-53531", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:rhivos:1", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat In-Vehicle Operating System 1"}], "public_date": "2025-10-01T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2023-53531\nhttps://nvd.nist.gov/vuln/detail/CVE-2023-53531\nhttps://lore.kernel.org/linux-cve-announce/2025100136-CVE-2023-53531-3c7c@gregkh/T"], "threat_severity": "Moderate"}

{"created": "2025-10-02T08:38:31.627212+00:00", "updated": "2025-10-02T08:38:31.627284+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}