CVE-2026-89790Hinoki check available

Kernel crash via IPv6 route rebalance race

Published Sep 16, 2026 · Updated Sep 16, 2026

Divide-by-zero in Linux 6.16 IPv6 routing allows local users with CAP_NET_ADMIN to crash the kernel through concurrent routing updates. rt6_multipath_rebalance totals eligible nexthop weights before a lock-free second pass; a concurrent link-down-policy change can leave a zero total while rt6_upper_bound_set divides by it. Exploitation requires privileged route and policy updates timed across both passes, and the demonstrated consequence is a kernel Oops and service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Divide-by-zero in Linux 6.16 IPv6 routing allows local users with CAP_NET_ADMIN to crash the kernel through concurrent routing updates. rt6_multipath_rebalance totals eligible nexthop weights before a lock-free second pass; a concurrent link-down-policy change can leave a zero total while rt6_upper_bound_set divides by it. Exploitation requires privileged route and policy updates timed across both passes, and the demonstrated consequence is a kernel Oops and service interruption.

The record

CVE
CVE-2026-89790
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.16
  2. Affected versionversion=bd11ff421d36abdb585b9104fa70057bf01b3110 <d2c26c2911dd1a363c488add4fb63eb5f0f28f87
  3. Affected versionversion=bd11ff421d36abdb585b9104fa70057bf01b3110 <f30cf8fd9872299c0c27f9916252ba2b9f422dce
  4. Affected versionversion=bd11ff421d36abdb585b9104fa70057bf01b3110 <f82b5dbb2fef65b52a62d5ffe05e0483c4385a83

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=6.16; version=bd11ff421d36abdb585b9104fa70057bf01b3110 <d2c26c2911dd1a363c488add4fb63eb5f0f28f87; version=bd11ff421d36abdb585b9104fa70057bf01b3110 <f30cf8fd9872299c0c27f9916252ba2b9f422dce; version=bd11ff421d36abdb585b9104fa70057bf01b3110 <f82b5dbb2fef65b52a62d5ffe05e0483c4385a83

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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