{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-17523", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-07-27T08:19:11.242Z", "datePublished": "2026-07-27T08:58:58.143Z", "dateUpdated": "2026-09-10T05:50:20.384Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-10T05:50:20.384Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet\n\nThis patch switches the timer to HRTIMER_MODE_SOFT, which executed the\ntimer callback in softirq context and removes the hrtimer_tasklet."}], "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 - The UAF is in bcm_remove_op() hrtimer/tasklet teardown, reached only via local PF_CAN/CAN_BCM syscalls (socket/connect/sendmsg TX_SETUP or RX_SETUP with STARTTIMER, then close or TX_DELETE/RX_DELETE). Remote IP services or CAN bus frames alone cannot close the socket or delete the op.\nAC:L - The attacker controls both sides of the race: they arm cyclic TX/RX hrtimers with attacker-chosen microsecond intervals, then delete the op or close the socket, hitting the TOCTOU between tasklet-state checks and hrtimer_active() in bcm_remove_op(). The window is retryable until the scheduled tasklet runs on the freed object.\nPR:L - can_create(), bcm_connect(), and bcm_sendmsg() have no capability checks. RX_SETUP with ifindex 0 starts timeout timers without a CAN device, so any unprivileged local user (including via user namespaces / vcan) can create BCM ops and trigger teardown.\nUI:N - Exploitation requires only the attacker opening a BCM socket, installing timer-armed TX_SETUP/RX_SETUP ops, and closing or deleting them; no victim action such as mounting a filesystem or opening a file is needed.\nS:U - The use-after-free corrupts kernel heap state in the same kernel security domain, enabling local privilege escalation or crash; it does not by itself cross a VM, guest-to-host, or IOMMU boundary.\nC:H - bcm_op is a kmalloc object that embeds tasklet_struct; after the hrtimer hardirq callback schedules a tasklet that bcm_remove_op() misses, the tasklet runs on freed memory. Heap reuse of tsklet.func/data and UAF reads in bcm_send_to_user()/bcm_can_tx() enable arbitrary kernel disclosure.\nI:H - The same UAF lets a sprayed tasklet_struct hijack tsklet.func for arbitrary kernel execution, and bcm_tx_timeout_tsklet()/bcm_can_tx() write through freed op fields (frames, sock, timers), providing arbitrary write and control-flow hijack primitives.\nA:H - A scheduled tasklet running after kfree(op) dereferences the freed bcm_op (and its frames/sk pointers), causing kernel oops/panic even when the UAF is not fully turned into code execution."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/can/bcm.c"], "versions": [{"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "79305a826f872fe446c6fbf8450f515053ef6951", "status": "affected", "versionType": "git"}, {"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68", "status": "affected", "versionType": "git"}, {"version": "0", "lessThan": "4.19.226", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/can/bcm.c"], "versions": [{"version": "4.19.226", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.4", "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:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.19.226"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionEndExcluding": "5.4"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/79305a826f872fe446c6fbf8450f515053ef6951"}, {"url": "https://git.kernel.org/stable/c/bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68"}], "title": "can: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-07-27T13:44:24.567768Z", "id": "CVE-2026-17523", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-27T13:44:45.277Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-17523", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-07-27T13:44:24.567768Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-27T13:44:29.321Z"}}], "cna": {"title": "can: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet", "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "79305a826f872fe446c6fbf8450f515053ef6951", "versionType": "git"}, {"status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68", "versionType": "git"}, {"status": "affected", "version": "0", "lessThan": "4.19.226", "versionType": "semver"}], "programFiles": ["net/can/bcm.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "unaffected", "version": "4.19.226", "versionType": "semver", "lessThanOrEqual": "4.19.*"}, {"status": "unaffected", "version": "5.4", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/can/bcm.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/79305a826f872fe446c6fbf8450f515053ef6951"}, {"url": "https://git.kernel.org/stable/c/bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet\n\nThis patch switches the timer to HRTIMER_MODE_SOFT, which executed the\ntimer callback in softirq context and removes the hrtimer_tasklet."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "4.19.226"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.4"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-09-09T07:28:55.352Z"}}}, "cveMetadata": {"cveId": "CVE-2026-17523", "state": "PUBLISHED", "dateUpdated": "2026-09-09T07:28:55.352Z", "dateReserved": "2026-07-27T08:19:11.242Z", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "datePublished": "2026-07-27T08:58:58.143Z", "assignerShortName": "redhat"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/can/bcm.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "79305a826f872fe446c6fbf8450f515053ef6951", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}, {"lessThan": "bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68", "status": "affected", "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "versionType": "git"}, {"lessThan": "4.19.226", "status": "affected", "version": "0", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/can/bcm.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThanOrEqual": "4.19.*", "status": "unaffected", "version": "4.19.226", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "5.4", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: bcm: switch timer to HRTIMER_MODE_SOFT and remove hrtimer_tasklet\n\nThis patch switches the timer to HRTIMER_MODE_SOFT, which executed the\ntimer callback in softirq context and removes the hrtimer_tasklet."}], "id": "CVE-2026-17523", "lastModified": "2026-09-10T06:17:05.037", "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"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-17523", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-07-27T13:44:24.567768Z", "version": "2.0.3"}}]}, "published": "2026-07-27T10:16:36.270", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/79305a826f872fe446c6fbf8450f515053ef6951"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bf74aa86e111aa3b2fbb25db37e3a3fab71b5b68"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Awaiting Analysis"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": null}], "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": null}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "Red Hat Enterprise Linux 8", "source": "cna", "vendor": "Red Hat"}, "product": "enterprise_linux", "vendor": "redhat"}], "created": "2026-07-27T15:22:59.048696+00:00", "title": "Kernel Timer Context Switch Fix in BCM Driver", "updated": "2026-09-10T09:00:06.863960+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel", "redhat", "redhat$PRODUCT$enterprise_linux"]}