CVE-2026-31420
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 5.5 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-667
- Record status
- Modified
Affected
- Linux Kernel < 6.19.12
- Linux Kernel 7.0
Attack profile CVSS 3.1 · 5.5
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-31420.md and follow it. Check whether this project is affected by CVE-2026-31420. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/c9bc352f716d1bebfe43354bce539ec2d0223b30
- https://git.kernel.org/stable/c/fa6e24963342de4370e3a3c9af41e38277b74cf3
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