---
id: CVE-2025-68813
title: 'ipvs: fix ipv4 null-ptr-deref in route error path'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipvs: fix ipv4 null-ptr-deref in route error path

  The IPv4 code path in __ip_vs_get_out_rt() calls dst_link_failure()
  without ensuring skb->dev is set, leading to a NU…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b <
    dd72a93c80408f06327dd2d956eb1a656d0b5903
  - >-
    Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b <
    312d7cd88882fc6cadcc08b02287497aaaf94bcd
  - >-
    Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b <
    cdeff10851c37a002d87a035818ebd60fdb74447
  - >-
    Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b <
    4729ff0581fbb7ad098b6153b76b6f5aac94618a
  - >-
    Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b <
    25ab24df31f7af843c96a38e0781b9165216e1a8
  - >-
    Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b <
    689a627d14788ad772e0fa24c2e57a23dbc7ce90
  - >-
    Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b <
    ad891bb3d079a46a821bf2b8867854645191bab0
  - Linux 6c2fa855d8178699706b1192db2f1f8102b0ba1e
  - Linux fbf569d2beee2a4a7a0bc8b619c26101d1211a88
  - Linux ff71f99d5fb2daf54340e8b290d0bc4e6b4c1d38
  - Linux 3d988fcddbe7b8673a231958bd2fba61b5a7ced9
  - Linux 8a430e56a6485267a1b2d3747209d26c54d1a34b
  - Linux 6bd1ee0a993fc9574ae43c1994c54a60cb23a380
  - Linux >= 3.18.139 < 3.19
  - Linux >= 4.4.179 < 4.5
  - Linux >= 4.9.171 < 4.10
  - Linux >= 4.14.114 < 4.15
  - Linux >= 4.19.37 < 4.20
  - Linux >= 5.0.10 < 5.1
  - Linux 5.1
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-06-16T19:15:40.029608Z'
published: '2026-01-13'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T18:05:08.415Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-68813'
references:
  - url: 'https://git.kernel.org/stable/c/dd72a93c80408f06327dd2d956eb1a656d0b5903'
  - url: 'https://git.kernel.org/stable/c/312d7cd88882fc6cadcc08b02287497aaaf94bcd'
  - url: 'https://git.kernel.org/stable/c/cdeff10851c37a002d87a035818ebd60fdb74447'
  - url: 'https://git.kernel.org/stable/c/4729ff0581fbb7ad098b6153b76b6f5aac94618a'
  - url: 'https://git.kernel.org/stable/c/25ab24df31f7af843c96a38e0781b9165216e1a8'
  - url: 'https://git.kernel.org/stable/c/689a627d14788ad772e0fa24c2e57a23dbc7ce90'
  - url: 'https://git.kernel.org/stable/c/ad891bb3d079a46a821bf2b8867854645191bab0'
tags:
  - cve.org
epss: 0.00207
epssPercentile: 0.10158
ingestedAt: '2026-10-19T18:35:50.150Z'
---

## Overview

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

ipvs: fix ipv4 null-ptr-deref in route error path

The IPv4 code path in __ip_vs_get_out_rt() calls dst_link_failure()
without ensuring skb->dev is set, leading to a NULL pointer dereference
in fib_compute_spec_dst() when ipv4_link_failure() attempts to send
ICMP destination unreachable messages.

The issue emerged after commit ed0de45a1008 ("ipv4: recompile ip options
in ipv4_link_failure") started calling __ip_options_compile() from
ipv4_link_failure(). This code path eventually calls fib_compute_spec_dst()
which dereferences skb->dev. An attempt was made to fix the NULL skb->dev
dereference in commit 0113d9c9d1cc ("ipv4: fix null-deref in
ipv4_link_failure"), but it only addressed the immediate dev_net(skb->dev)
dereference by using a fallback device. The fix was incomplete because
fib_compute_spec_dst() later in the call chain still accesses skb->dev
directly, which remains NULL when IPVS calls dst_link_failure().

The crash occurs when:
1. IPVS processes a packet in NAT mode with a misconfigured destination
2. Route lookup fails in __ip_vs_get_out_rt() before establishing a route
3. The error path calls dst_link_failure(skb) with skb->dev == NULL
4. ipv4_link_failure() → ipv4_send_dest_unreach() →
   __ip_options_compile() → fib_compute_spec_dst()
5. fib_compute_spec_dst() dereferences NULL skb->dev

Apply the same fix used for IPv6 in commit 326bf17ea5d4 ("ipvs: fix
ipv6 route unreach panic"): set skb->dev from skb_dst(skb)->dev before
calling dst_link_failure().

KASAN: null-ptr-deref in range [0x0000000000000328-0x000000000000032f]
CPU: 1 PID: 12732 Comm: syz.1.3469 Not tainted 6.6.114 #2
RIP: 0010:__in_dev_get_rcu include/linux/inetdevice.h:233
RIP: 0010:fib_compute_spec_dst+0x17a/0x9f0 net/ipv4/fib_frontend.c:285
Call Trace:
  <TASK>
  spec_dst_fill net/ipv4/ip_options.c:232
  spec_dst_fill net/ipv4/ip_options.c:229
  __ip_options_compile+0x13a1/0x17d0 net/ipv4/ip_options.c:330
  ipv4_send_dest_unreach net/ipv4/route.c:1252
  ipv4_link_failure+0x702/0xb80 net/ipv4/route.c:1265
  dst_link_failure include/net/dst.h:437
  __ip_vs_get_out_rt+0x15fd/0x19e0 net/netfilter/ipvs/ip_vs_xmit.c:412
  ip_vs_nat_xmit+0x1d8/0xc80 net/netfilter/ipvs/ip_vs_xmit.c:764

## Affected

- `Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b < dd72a93c80408f06327dd2d956eb1a656d0b5903`
- `Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b < 312d7cd88882fc6cadcc08b02287497aaaf94bcd`
- `Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b < cdeff10851c37a002d87a035818ebd60fdb74447`
- `Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b < 4729ff0581fbb7ad098b6153b76b6f5aac94618a`
- `Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b < 25ab24df31f7af843c96a38e0781b9165216e1a8`
- `Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b < 689a627d14788ad772e0fa24c2e57a23dbc7ce90`
- `Linux >= ed0de45a1008991fdaa27a0152befcb74d126a8b < ad891bb3d079a46a821bf2b8867854645191bab0`
- `Linux 6c2fa855d8178699706b1192db2f1f8102b0ba1e`
- `Linux fbf569d2beee2a4a7a0bc8b619c26101d1211a88`
- `Linux ff71f99d5fb2daf54340e8b290d0bc4e6b4c1d38`
- `Linux 3d988fcddbe7b8673a231958bd2fba61b5a7ced9`
- `Linux 8a430e56a6485267a1b2d3747209d26c54d1a34b`
- `Linux 6bd1ee0a993fc9574ae43c1994c54a60cb23a380`
- `Linux >= 3.18.139 < 3.19`
- `Linux >= 4.4.179 < 4.5`
- `Linux >= 4.9.171 < 4.10`
- `Linux >= 4.14.114 < 4.15`
- `Linux >= 4.19.37 < 4.20`
- `Linux >= 5.0.10 < 5.1`
- `Linux 5.1`

## Remediation

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