CVE-2026-31420 (GCVE-0-2026-31420)

Vulnerability from cvelistv5 – Published: 2026-04-13 13:40 – Updated: 2026-06-01 16:11
VLAI
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.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 20f6a05ef63594feb0c6dfbd629da0448b43124d , < 630a15a31c2034b5b697f4aabc769b9d80d82446 (git)
Affected: 20f6a05ef63594feb0c6dfbd629da0448b43124d , < e8ec80430bfa520e7352155d6ac632e527cba7aa (git)
Affected: 20f6a05ef63594feb0c6dfbd629da0448b43124d , < c9bc352f716d1bebfe43354bce539ec2d0223b30 (git)
Affected: 20f6a05ef63594feb0c6dfbd629da0448b43124d , < fa6e24963342de4370e3a3c9af41e38277b74cf3 (git)
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Linux Linux Affected: 5.8
Unaffected: 0 , < 5.8 (semver)
Unaffected: 6.12.92 , ≤ 6.12.* (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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{
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    "datePublished": "2026-04-13T13:40:24.594Z",
    "dateReserved": "2026-03-09T15:48:24.088Z",
    "dateUpdated": "2026-06-01T16:11:26.083Z",
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    "redhat_vex": {
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      "cve": "CVE-2026-31420",
      "id": "CVE-2026-31420",
      "initial_release_date": "2026-04-13T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bridge: mrp: reject zero test interval to avoid OOM panic",
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.