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CVE-2026-63977 (GCVE-0-2026-63977)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:56 – Updated: 2026-08-05 12:37
VLAI
Title
dpll: zl3073x: use __dpll_device_change_ntf() and remove change_work
Summary
In the Linux kernel, the following vulnerability has been resolved: dpll: zl3073x: use __dpll_device_change_ntf() and remove change_work The change_work was introduced to send device change notifications from DPLL device callbacks without deadlocking on dpll_lock, since the callbacks are already invoked under that lock. Now that __dpll_device_change_ntf() is exported for callers that already hold dpll_lock, use it directly and remove the change_work infrastructure entirely. This eliminates a race condition where change_work could be re-scheduled after cancel_work_sync() during device teardown, potentially causing the handler to dereference a freed or NULL dpll_dev pointer.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 9363b4837659d1b7ee04cfa714373ce4b4b8269f , < e7a33807fb3f87a855993474ac21684ce105927b (git)
Affected: 9363b4837659d1b7ee04cfa714373ce4b4b8269f , < d733f519f6443540f8359461a34e3b0042099bbe (git)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 7.0.12 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/dpll/zl3073x/dpll.c",
            "drivers/dpll/zl3073x/dpll.h"
          ],
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          "vendor": "Linux",
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              "operator": "OR"
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          "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."
        }
      ],
      "metrics": [
        {
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:37:48.157Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "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",
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        "engine": "bippy-1.2.0"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63977",
    "datePublished": "2026-07-19T14:56:01.889Z",
    "dateReserved": "2026-07-19T07:54:57.024Z",
    "dateUpdated": "2026-08-05T12:37:48.157Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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    "epss": {
      "cve": "CVE-2026-63977",
      "date": "2026-09-05",
      "epss": "0.0012",
      "percentile": "0.0208"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-22T07:06:01+00:00",
      "cve": "CVE-2026-63977",
      "id": "CVE-2026-63977",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: dpll: zl3073x: use __dpll_device_change_ntf() and remove change_work",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63977.json",
      "version": "3"
    }
  }
}



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