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bridge: mrp: reject zero test interval to avoid OOM panic

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: bridge: mrp: reject zero test interval to avoid OOM panic br_mrp_start_test() and br_mrp_start_in_test() accept the user-supplied interval value from netlink without validation. When interval is 0, usecs_to_jiffies(0) yields 0, causing the delayed work (br_mrp_test_work_expired / br_mrp_in_test_work_expired) to reschedule itself with zero delay. This creates a tight loop on system_percpu_wq that allocates and transmits MRP test frames at maximum rate, exhausting all system memory and causing a kernel panic via OOM deadlock. The same zero-interval issue applies to br_mrp_start_in_test_parse() for interconnect test frames. Use NLA_POLICY_MIN(NLA_U32, 1) in the nla_policy tables for both IFLA_BRIDGE_MRP_START_TEST_INTERVAL and IFLA_BRIDGE_MRP_START_IN_TEST_INTERVAL, so zero is rejected at the netlink attribute parsing layer before the value ever reaches the workqueue scheduling code. This is consistent with how other bridge subsystems (br_fdb, br_mst) enforce range constraints on netlink attributes.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.270, 5.15.221, 6.1.188, 6.12.92, 6.18.34, 6.19.12, 6.6.157
CVEs
CVE-2026-31420
Confirmed fixed CVEs
Not specified
Updated in this feed
5 Nov 2026, 04:24 UTC · Revision 1

Source evidence

bridge: mrp: reject zero test interval to avoid OOM panic

core-osv · Original source

Published 13 Apr 2026, 13:40 UTC

In the Linux kernel, the following vulnerability has been resolved: bridge: mrp: reject zero test interval to avoid OOM panic br_mrp_start_test() and br_mrp_start_in_test() accept the user-supplied interval value from netlink without validation. When interval is 0, usecs_to_jiffies(0) yields 0, causing the delayed work (br_mrp_test_work_expired / br_mrp_in_test_work_expired) to reschedule itself with zero delay. This creates a tight loop on system_percpu_wq that allocates and transmits MRP test frames at maximum rate, exhausting all system memory and causing a kernel panic via OOM deadlock. The same zero-interval issue applies to br_mrp_start_in_test_parse() for interconnect test frames. Use NLA_POLICY_MIN(NLA_U32, 1) in the nla_policy tables for both IFLA_BRIDGE_MRP_START_TEST_INTERVAL and IFLA_BRIDGE_MRP_START_IN_TEST_INTERVAL, so zero is rejected at the netlink attribute parsing layer before the value ever reaches the workqueue scheduling code. This is consistent with how other bridge subsystems (br_fdb, br_mst) enforce range constraints on netlink attributes.

osv:CVE-2026-31420

Kernel

Fixed versions: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.92, 6.18.34, 6.19.12

Complete source record
{
  "id": "c40493484d63ead7129e7fb449f552f466dcf59c92dca4e30015226cb61d9194",
  "url": "https://osv.dev/vulnerability/CVE-2026-31420",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bridge: mrp: reject zero test interval to avoid OOM panic",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bridge: mrp: reject zero test interval to avoid OOM panic br_mrp_start_test() and br_mrp_start_in_test() accept the user-supplied interval value from netlink without validation. When interval is 0, usecs_to_jiffies(0) yields 0, causing the delayed work (br_mrp_test_work_expired / br_mrp_in_test_work_expired) to reschedule itself with zero delay. This creates a tight loop on system_percpu_wq that allocates and transmits MRP test frames at maximum rate, exhausting all system memory and causing a kernel panic via OOM deadlock. The same zero-interval issue applies to br_mrp_start_in_test_parse() for interconnect test frames. Use NLA_POLICY_MIN(NLA_U32, 1) in the nla_policy tables for both IFLA_BRIDGE_MRP_START_TEST_INTERVAL and IFLA_BRIDGE_MRP_START_IN_TEST_INTERVAL, so zero is rejected at the netlink attribute parsing layer before the value ever reaches the workqueue scheduling code. This is consistent with how other bridge subsystems (br_fdb, br_mst) enforce range constraints on netlink attributes.",
    "evidence": "osv:CVE-2026-31420",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.270",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.221",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.92",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.34",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.12",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-31420",
      "aliases": [
        "CVE-2026-31420"
      ],
      "affected": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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              "type": "ECOSYSTEM",
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                  "introduced": "5.8.0"
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
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              ]
            },
            {
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                {
                  "introduced": "5.16.0"
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            },
            {
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            },
            {
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            {
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31420.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:42.841167181Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1ec86b4b9e28170a2565cf36f0e6e2b96b55134d",
        "https://git.kernel.org/stable/c/2120bd8546cd6a63c558d135773aa8f41c8259fc",
        "https://git.kernel.org/stable/c/610073ffb77ffd2b5eca182d2ac264de4834a175",
        "https://git.kernel.org/stable/c/630a15a31c2034b5b697f4aabc769b9d80d82446",
        "https://git.kernel.org/stable/c/c9bc352f716d1bebfe43354bce539ec2d0223b30",
        "https://git.kernel.org/stable/c/e8ec80430bfa520e7352155d6ac632e527cba7aa",
        "https://git.kernel.org/stable/c/ec8850be9b2b3beac1c7967d95f169dd2785979d",
        "https://git.kernel.org/stable/c/fa6e24963342de4370e3a3c9af41e38277b74cf3",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31420.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-31420",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31420.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-31420",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 510248,
  "published_at": "2026-04-13T13:40:24.594+00:00"
}