CVE-2026-89499 (GCVE-0-2026-89499)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:43 – Updated: 2026-10-19 08:47
VLAI
Title
ring-buffer: Stop remote reader update when page swap fails
Summary
In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Stop remote reader update when page swap fails The remote swap_reader_page callback can return -EBUSY when the writer moves the head before the remote catches it, particularly during an event storm on a small buffer. __rb_get_reader_page_from_remote() currently warns about that failure but continues with the unchanged reader ID and rearranges the local page list as though the swap succeeded. Handle the callback failure as a recoverable error. Report it with pr_warn_ratelimited() and return NULL. Callers already handle a NULL reader page as a failed attempt. This avoids splicing the same page as both the previous and new reader without flooding the log under contention.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6643 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 2e67fabd8b77c4f482df9b211bca1b495c6c2c24 , < a14a97048e48471e283d76879b83d2ae323e0722 (git)
Affected: 2e67fabd8b77c4f482df9b211bca1b495c6c2c24 , < 5eab74874d11160725c42ab676ba97a797a362eb (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Stop remote reader update when page swap fails\n\nThe remote swap_reader_page callback can return -EBUSY when the writer\nmoves the head before the remote catches it, particularly during an event\nstorm on a small buffer. __rb_get_reader_page_from_remote() currently\nwarns about that failure but continues with the unchanged reader ID and\nrearranges the local page list as though the swap succeeded.\n\nHandle the callback failure as a recoverable error. Report it with\npr_warn_ratelimited() and return NULL. Callers already handle a NULL reader\npage as a failed attempt. This avoids splicing the same page as both the\nprevious and new reader without flooding the log under contention."
        }
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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"
          },
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              "value": "AV:L - The bug is reached only by a local read of tracefs remotes/*/trace_pipe or remotes/*/trace, which calls ring_buffer_peek/consume then rb_get_reader_page() and __rb_get_reader_page_from_remote(). No network, adjacent-radio, or physical-device path reaches this remote reader swap.\nAC:L - An attacker with tracefs access sets a small remotes/*/buffer_size_kb, enables tracing, generates an event storm via remotes/*/write_event or KVM hyp events, and reads trace_pipe. That is the documented -EBUSY case; the attacker controls writer load and the reader swap, so the failed-swap path is reliably hit.\nPR:L - remotes/ files are mode 0440/0640 and use custom fops with no capable() or tracing_check_open_get_tr() check, only DAC. tracing-gid mounts on Android eng/Perfetto, ChromeOS, and developer kernels grant this to unprivileged users, matching prior CNA tracefs scores.\nUI:N - The attacker opens, configures, and reads their own remotes/*/trace_pipe and related tracefs files. No separate victim mount, click, or other user action is required.\nS:U - The corruption is of host kernel ring-buffer buffer_page lists and reader metadata in the same OS security authority. A host-local tracefs user cannot use this as a VM/IOMMU/guest-to-host escape.\nC:H - On swap failure the kernel still splices the unchanged reader page into the list and shares it with the remote writer. Torn event headers make rb_event_length() return unbounded sizes, and later peeks follow corrupted buffer_page pointers, enabling out-of-bounds kernel reads.\nI:H - __rb_get_reader_page_from_remote() writes list.next/list.prev as if the swap succeeded, creating a self-referential reader and unlinking the real head. Subsequent swaps and rb_inc_page/rb_list_head_clear store further pointers on that corrupted topology, which is exploitable kernel metadata corruption.\nA:H - The failed-swap path hits WARN_ON_ONCE(prev_reader == new_reader), can infinite-loop walking the spliced list, and oopses on corrupted page pointers. panic_on_warn makes those WARNs a kernel panic, and the attacker can retrigger the path at will."
            }
          ]
        }
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      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:47:50.883Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/a14a97048e48471e283d76879b83d2ae323e0722"
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    "cveId": "CVE-2026-89499",
    "datePublished": "2026-09-11T19:43:48.752Z",
    "dateReserved": "2026-09-11T19:38:34.715Z",
    "dateUpdated": "2026-10-19T08:47:50.883Z",
    "state": "PUBLISHED"
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      "date": "2026-11-10",
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Stop remote reader update when page swap fails\n\nThe remote swap_reader_page callback can return -EBUSY when the writer\nmoves the head before the remote catches it, particularly during an event\nstorm on a small buffer. __rb_get_reader_page_from_remote() currently\nwarns about that failure but continues with the unchanged reader ID and\nrearranges the local page list as though the swap succeeded.\n\nHandle the callback failure as a recoverable error. Report it with\npr_warn_ratelimited() and return NULL. Callers already handle a NULL reader\npage as a failed attempt. This avoids splicing the same page as both the\nprevious and new reader without flooding the log under contention."
          }
        ],
        "id": "CVE-2026-89499",
        "lastModified": "2026-10-19T09:17:44.073",
        "metrics": {
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            {
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                "attackVector": "LOCAL",
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                "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"
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-11T20:19:32.063",
        "references": [
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
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    "redhat_vex": {
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      "current_release_date": "2026-11-06T01:16:29+00:00",
      "cve": "CVE-2026-89499",
      "id": "CVE-2026-89499",
      "initial_release_date": "2026-09-11T00:00:00+00:00",
      "product_status:known_not_affected": "203",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ring-buffer: Stop remote reader update when page swap fails",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89499.json",
      "version": "3"
    }
  }
}



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