---
id: CVE-2026-80838
title: 'vxlan: keep the last remote linked during FDB flush'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  vxlan: keep the last remote linked during FDB flush

  A non-nexthop FDB entry is expected to have at least one remote while it
  remains reachable through the FDB hash tab…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <
    2a7c2f00843225d5f037676bca649321f3d024c7
  - >-
    Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <
    a8820c8a7718327e96849782033e7c85a0f6bcfe
  - >-
    Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <
    8ba68fd6cdd1e3c92b92f25c7e48bf7bd51a183c
  - >-
    Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <
    4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab
  - >-
    Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f <
    d5d4a7b538b52db63927773a8905fcd9f78a42e2
  - Linux 6.7
published: '2026-09-04'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:44:30.457Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80838'
references:
  - url: 'https://git.kernel.org/stable/c/2a7c2f00843225d5f037676bca649321f3d024c7'
  - url: 'https://git.kernel.org/stable/c/a8820c8a7718327e96849782033e7c85a0f6bcfe'
  - url: 'https://git.kernel.org/stable/c/8ba68fd6cdd1e3c92b92f25c7e48bf7bd51a183c'
  - url: 'https://git.kernel.org/stable/c/4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab'
  - url: 'https://git.kernel.org/stable/c/d5d4a7b538b52db63927773a8905fcd9f78a42e2'
tags:
  - cve.org
epss: 0.00168
epssPercentile: 0.05686
ingestedAt: '2026-10-19T09:16:01.499Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

vxlan: keep the last remote linked during FDB flush

A non-nexthop FDB entry is expected to have at least one remote while it
remains reachable through the FDB hash table. A filtered bulk flush
violates this invariant when every remote matches: It unlinks the last
remote in vxlan_fdb_dst_destroy() and only afterwards tells vxlan_flush()
to destroy the parent FDB entry.

An RCU reader can find the parent during this interval.
first_remote_rcu() then applies list_entry_rcu() to the empty list head,
producing an invalid remote pointer that the receive learning path can
read from and write to.

When a matching remote is the sole remaining remote, leave it linked and
ask the caller to destroy the entire FDB entry. vxlan_fdb_destroy() keeps
the remote attached while sending the deletion notification and removing
the parent from the lookup structures.

## Affected

- `Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f < 2a7c2f00843225d5f037676bca649321f3d024c7`
- `Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f < a8820c8a7718327e96849782033e7c85a0f6bcfe`
- `Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f < 8ba68fd6cdd1e3c92b92f25c7e48bf7bd51a183c`
- `Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f < 4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab`
- `Linux >= c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f < d5d4a7b538b52db63927773a8905fcd9f78a42e2`
- `Linux 6.7`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.