CVE-2026-63977

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Now that\n__dpll_device_change_ntf() is exported for callers that already\nhold dpll_lock, use it directly and remove the change_work\ninfrastructure entirely.\n\nThis eliminates a race condition where change_work could be\nre-scheduled after cancel_work_sync() during device teardown,\npotentially causing the handler to dereference a freed or NULL\ndpll_dev pointer."}], "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 bug is reached only through the DPLL generic-netlink interface (`DPLL_CMD_DEVICE_SET` with `DPLL_A_PHASE_OFFSET_AVG_FACTOR`), which requires a local `sendmsg()`/netlink syscall. The zl3073x driver is an on-board I2C/SPI timing chip driver and is not exposed via remote network packet handling.\nAC:L - Exploitation is a use-after-free race where the attacker controls the scheduling side by repeatedly issuing concurrent DPLL netlink SET requests (`parallel_ops` is enabled). The teardown window is created during sibling-DPLL unregistration in `zl3073x_dev_stop()`, which occurs on driver remove/reboot/maintenance that the attacker can time against.\nPR:L - All DPLL netlink operations are gated by `GENL_ADMIN_PERM`, which requires `CAP_NET_ADMIN`. That capability is obtainable by an unprivileged user via user namespaces (`unshare -Urn`), and the DPLL family is `netnsok`, so this is not restricted to real init-namespace root.\nUI:N - Triggering the race requires only automated netlink traffic from the attacker; no victim user action such as opening a file or mounting a filesystem is needed.\nS:U - Impact is kernel memory corruption and potential privilege escalation within the same kernel security authority. This is not a VM/guest escape or IOMMU boundary bypass.\nC:H - The race leaves a deferred work item that calls `dpll_device_change_ntf()` on a `dpll_dev` pointer that may already be freed, causing a classic use-after-free with reads of freed `struct dpll_device` fields (`id`, `clock_id`, `type`, etc.).\nI:H - Use-after-free of a heap-allocated `struct dpll_device` can be leveraged for controlled reuse and arbitrary kernel memory corruption, including potential control-flow hijacking, not merely a benign crash.\nA:H - Dereferencing a freed or NULL `dpll_dev` from the workqueue handler can cause a kernel oops/panic during device teardown, and UAF conditions inherently threaten system availability even when full exploitation is not attempted."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/dpll/zl3073x/dpll.c", "drivers/dpll/zl3073x/dpll.h"], "versions": [{"version": "9363b4837659d1b7ee04cfa714373ce4b4b8269f", "lessThan": "e7a33807fb3f87a855993474ac21684ce105927b", "status": "affected", "versionType": "git"}, {"version": "9363b4837659d1b7ee04cfa714373ce4b4b8269f", "lessThan": "d733f519f6443540f8359461a34e3b0042099bbe", "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/dpll/zl3073x/dpll.c", "drivers/dpll/zl3073x/dpll.h"], "versions": [{"version": "6.18", "status": "affected"}, {"version": "0", "lessThan": "6.18", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "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": "6.18", "versionEndExcluding": "7.0.12"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/e7a33807fb3f87a855993474ac21684ce105927b"}, {"url": "https://git.kernel.org/stable/c/d733f519f6443540f8359461a34e3b0042099bbe"}], "title": "dpll: zl3073x: use __dpll_device_change_ntf() and remove change_work", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-63977", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T15:34:28.879643Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-362", "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"}]}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-19T20:18:00.021Z"}}]}}

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The zl3073x driver is an on-board I2C/SPI timing chip driver and is not exposed via remote network packet handling.\nAC:L - Exploitation is a use-after-free race where the attacker controls the scheduling side by repeatedly issuing concurrent DPLL netlink SET requests (`parallel_ops` is enabled). The teardown window is created during sibling-DPLL unregistration in `zl3073x_dev_stop()`, which occurs on driver remove/reboot/maintenance that the attacker can time against.\nPR:L - All DPLL netlink operations are gated by `GENL_ADMIN_PERM`, which requires `CAP_NET_ADMIN`. That capability is obtainable by an unprivileged user via user namespaces (`unshare -Urn`), and the DPLL family is `netnsok`, so this is not restricted to real init-namespace root.\nUI:N - Triggering the race requires only automated netlink traffic from the attacker; no victim user action such as opening a file or mounting a filesystem is needed.\nS:U - Impact is kernel memory corruption and potential privilege escalation within the same kernel security authority. This is not a VM/guest escape or IOMMU boundary bypass.\nC:H - The race leaves a deferred work item that calls `dpll_device_change_ntf()` on a `dpll_dev` pointer that may already be freed, causing a classic use-after-free with reads of freed `struct dpll_device` fields (`id`, `clock_id`, `type`, etc.).\nI:H - Use-after-free of a heap-allocated `struct dpll_device` can be leveraged for controlled reuse and arbitrary kernel memory corruption, including potential control-flow hijacking, not merely a benign crash.\nA:H - Dereferencing a freed or NULL `dpll_dev` from the workqueue handler can cause a kernel oops/panic during device teardown, and UAF conditions inherently threaten system availability even when full exploitation is not attempted."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "9363b4837659d1b7ee04cfa714373ce4b4b8269f", "lessThan": "e7a33807fb3f87a855993474ac21684ce105927b", "versionType": "git"}, {"status": "affected", "version": "9363b4837659d1b7ee04cfa714373ce4b4b8269f", "lessThan": "d733f519f6443540f8359461a34e3b0042099bbe", "versionType": "git"}], "programFiles": ["drivers/dpll/zl3073x/dpll.c", "drivers/dpll/zl3073x/dpll.h"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "6.18"}, {"status": "unaffected", "version": "0", "lessThan": "6.18", "versionType": "semver"}, {"status": "unaffected", "version": "7.0.12", "versionType": "semver", "lessThanOrEqual": "7.0.*"}, {"status": "unaffected", "version": "7.1", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["drivers/dpll/zl3073x/dpll.c", "drivers/dpll/zl3073x/dpll.h"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/e7a33807fb3f87a855993474ac21684ce105927b"}, {"url": "https://git.kernel.org/stable/c/d733f519f6443540f8359461a34e3b0042099bbe"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndpll: zl3073x: use __dpll_device_change_ntf() and remove change_work\n\nThe change_work was introduced to send device change notifications\nfrom DPLL device callbacks without deadlocking on dpll_lock, since\nthe callbacks are already invoked under that lock. Now that\n__dpll_device_change_ntf() is exported for callers that already\nhold dpll_lock, use it directly and remove the change_work\ninfrastructure entirely.\n\nThis eliminates a race condition where change_work could be\nre-scheduled after cancel_work_sync() during device teardown,\npotentially causing the handler to dereference a freed or NULL\ndpll_dev pointer."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.0.12", "versionStartIncluding": "6.18"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.1", "versionStartIncluding": "6.18"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:37:48.157Z"}}}, "cveMetadata": {"cveId": "CVE-2026-63977", "state": "PUBLISHED", "dateUpdated": "2026-10-19T20:18:00.021Z", "dateReserved": "2026-07-19T07:54:57.024Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-07-19T14:56:01.889Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

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{"bugzilla": {"description": "kernel: dpll: zl3073x: use __dpll_device_change_ntf() and remove change_work", "id": "2502379", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502379"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-476", "details": ["In the Linux kernel, the following vulnerability has been resolved:\ndpll: zl3073x: use __dpll_device_change_ntf() and remove change_work\nThe change_work was introduced to send device change notifications\nfrom DPLL device callbacks without deadlocking on dpll_lock, since\nthe callbacks are already invoked under that lock. Now that\n__dpll_device_change_ntf() is exported for callers that already\nhold dpll_lock, use it directly and remove the change_work\ninfrastructure entirely.\nThis eliminates a race condition where change_work could be\nre-scheduled after cancel_work_sync() during device teardown,\npotentially causing the handler to dereference a freed or NULL\ndpll_dev pointer.", "A flaw was found in the Linux kernel's `dpll: zl3073x` module. A race condition can occur during device teardown when a `change_work` operation is re-scheduled after a `cancel_work_sync()` call. This can lead to the system attempting to access a memory location that has been freed or is invalid, potentially causing a system crash and resulting in a denial of service."], "name": "CVE-2026-63977", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63977\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63977\nhttps://lore.kernel.org/linux-cve-announce/2026071901-CVE-2026-63977-be9d@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9363b4837659d1b7ee04cfa714373ce4b4b8269f,e7a33807fb3f87a855993474ac21684ce105927b)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9363b4837659d1b7ee04cfa714373ce4b4b8269f,d733f519f6443540f8359461a34e3b0042099bbe)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[6.18,6.18]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,6.18)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.12,7.1.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-21T06:15:01.896603+00:00", "updated": "2026-10-20T09:15:12.777178+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}