---
id: CVE-2026-74563
title: 'rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()

  rds_tcp_laddr_check() looks up a scoped IPv6 interface with
  dev_get_by_index_rcu(), drops t…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 <
    f8a8977af2134a1d91e5f9773cb7d9d53278c830
  - >-
    Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 <
    ba95bce5dfe6e2ef602a87e0557225f2934ccb5c
  - >-
    Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 <
    c4933624a6f416ecfcc31ab58d585da1207a0597
  - >-
    Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 <
    76dd48886eeeb5fcf2b837d2f4c3d17eebeac9ef
  - >-
    Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 <
    f0d1fb05d70c8a561cd8d0473bcacafa2fc137ff
  - >-
    Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 <
    b1d480fce05f857dc438080cd8c9244b84a83494
  - >-
    Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 <
    8398bc477d3cb3e2b018a5aaac2bec0f69acda30
  - >-
    Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 <
    78f75d632f74b8de0f081a128588f7c37d0d1164
  - Linux 4.19
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T19:00:11.789962Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:05:55.886Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74563'
references:
  - url: 'https://git.kernel.org/stable/c/f8a8977af2134a1d91e5f9773cb7d9d53278c830'
  - url: 'https://git.kernel.org/stable/c/ba95bce5dfe6e2ef602a87e0557225f2934ccb5c'
  - url: 'https://git.kernel.org/stable/c/c4933624a6f416ecfcc31ab58d585da1207a0597'
  - url: 'https://git.kernel.org/stable/c/76dd48886eeeb5fcf2b837d2f4c3d17eebeac9ef'
  - url: 'https://git.kernel.org/stable/c/f0d1fb05d70c8a561cd8d0473bcacafa2fc137ff'
  - url: 'https://git.kernel.org/stable/c/b1d480fce05f857dc438080cd8c9244b84a83494'
  - url: 'https://git.kernel.org/stable/c/8398bc477d3cb3e2b018a5aaac2bec0f69acda30'
  - url: 'https://git.kernel.org/stable/c/78f75d632f74b8de0f081a128588f7c37d0d1164'
tags:
  - cve.org
epss: 0.00117
epssPercentile: 0.01571
ingestedAt: '2026-10-16T19:46:24.343Z'
---

## Overview

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

rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()

rds_tcp_laddr_check() looks up a scoped IPv6 interface with
dev_get_by_index_rcu(), drops the RCU read-side lock, and only then
passes the bare struct net_device * into ipv6_chk_addr().

dev_get_by_index_rcu() only keeps the device alive within the same RCU
read-side section. After rcu_read_unlock(), a concurrent RTM_DELLINK can
free the net_device; ipv6_chk_addr() then dereferences the stale pointer
in __ipv6_chk_addr_and_flags() (e.g. l3mdev_master_dev_rcu(dev)), reading
freed memory.

Keep the RCU read-side lock held across the ipv6_chk_addr() call instead
of dropping it right after the lookup, so the device cannot be freed
while it is in use.

  BUG: KASAN: slab-use-after-free in __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)
  Read of size 8 at addr ffff8880106ec000 by task exploit/153
  Call Trace:
   ...
   kasan_report (mm/kasan/report.c:595)
   __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)
   ipv6_chk_addr (net/ipv6/addrconf.c:2031 net/ipv6/addrconf.c:1972)
   rds_tcp_laddr_check (net/rds/tcp.c:370)
   rds_bind (net/rds/bind.c:248)
   __sys_bind (net/socket.c:1920)
   __x64_sys_bind (net/socket.c:1956)
   do_syscall_64 (arch/x86/entry/syscall_64.c:63)
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)

## Affected

- `Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 < f8a8977af2134a1d91e5f9773cb7d9d53278c830`
- `Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 < ba95bce5dfe6e2ef602a87e0557225f2934ccb5c`
- `Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 < c4933624a6f416ecfcc31ab58d585da1207a0597`
- `Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 < 76dd48886eeeb5fcf2b837d2f4c3d17eebeac9ef`
- `Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 < f0d1fb05d70c8a561cd8d0473bcacafa2fc137ff`
- `Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 < b1d480fce05f857dc438080cd8c9244b84a83494`
- `Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 < 8398bc477d3cb3e2b018a5aaac2bec0f69acda30`
- `Linux >= eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 < 78f75d632f74b8de0f081a128588f7c37d0d1164`
- `Linux 4.19`

## Remediation

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