CVE-2026-46086

Local system crash via unstable bridge FDB pointer

Published May 27, 2026 · Updated May 27, 2026

NULL-pointer dereference in the Linux Kernel bridge FDB code allows local users to crash the system through a concurrent FDB update. The br_fdb_fillbuf() RCU reader checks f->dst, reloads it after fdb_delete_local() can replace it with NULL, and dereferences port_no. Low-privileged local access and an active Linux bridge exposing the brforward sysfs path are required; the consequence is limited to system availability.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL-pointer dereference in the Linux Kernel bridge FDB code allows local users to crash the system through a concurrent FDB update. The br_fdb_fillbuf() RCU reader checks f->dst, reloads it after fdb_delete_local() can replace it with NULL, and dereferences port_no. Low-privileged local access and an active Linux bridge exposing the brforward sysfs path are required; the consequence is limited to system availability.

The record

CVE
CVE-2026-46086
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 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=3.14
  2. Affected versionversion=960b589f86c74ce582922fcb996103271081f4de <0b9e4bbfb7c949151e3acd44ed4aa33614d2e110
  3. Affected versionversion=960b589f86c74ce582922fcb996103271081f4de <5424e678f9b304e148cf5dcc047cffc7a56a3bb5
  4. Affected versionversion=960b589f86c74ce582922fcb996103271081f4de <81af4137a30c4c2dc694dea8cacb180bd66000ef
  5. Affected versionversion=960b589f86c74ce582922fcb996103271081f4de <9a2d9d4e657b23dc21f24cf139e3aeff0b61341f
  6. Affected versionversion=960b589f86c74ce582922fcb996103271081f4de <df4601653201de21b487c3e7fffd464790cab808

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.14; version=960b589f86c74ce582922fcb996103271081f4de <0b9e4bbfb7c949151e3acd44ed4aa33614d2e110; version=960b589f86c74ce582922fcb996103271081f4de <5424e678f9b304e148cf5dcc047cffc7a56a3bb5; version=960b589f86c74ce582922fcb996103271081f4de <81af4137a30c4c2dc694dea8cacb180bd66000ef; version=960b589f86c74ce582922fcb996103271081f4de <9a2d9d4e657b23dc21f24cf139e3aeff0b61341f; version=960b589f86c74ce582922fcb996103271081f4de <df4601653201de21b487c3e7fffd464790cab808

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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