---
id: CVE-2026-98934
title: 'ipv6: sr: use skb_get_hash_net() in seg6_make_flowlabel()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: sr: use skb_get_hash_net() in seg6_make_flowlabel()

  Since commit d58e468b1112 ("flow_dissector: implements flow dissector
  BPF hook") __skb_flow_dissect() needs a…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 <
    4ab37e4f4a33c64d9e565dc8c4c3ed774f05c0e3
  - >-
    Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 <
    8fe3d6717f5536793727e60b7a0b7ec20c697def
  - >-
    Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 <
    53b21bc2df6e8ed538bceda93a5104a5fe6a8a84
  - >-
    Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 <
    086e8acb3a0e55f6d22d29fae2a4a3b1561bb766
  - >-
    Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 <
    8ec454dcd00ce3375119111c6394964455b36d0d
  - Linux 4.20
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T12:11:43.459Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98934'
references:
  - url: 'https://git.kernel.org/stable/c/4ab37e4f4a33c64d9e565dc8c4c3ed774f05c0e3'
  - url: 'https://git.kernel.org/stable/c/8fe3d6717f5536793727e60b7a0b7ec20c697def'
  - url: 'https://git.kernel.org/stable/c/53b21bc2df6e8ed538bceda93a5104a5fe6a8a84'
  - url: 'https://git.kernel.org/stable/c/086e8acb3a0e55f6d22d29fae2a4a3b1561bb766'
  - url: 'https://git.kernel.org/stable/c/8ec454dcd00ce3375119111c6394964455b36d0d'
tags:
  - cve.org
ingestedAt: '2026-10-23T13:24:55.563Z'
---

## Overview

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

ipv6: sr: use skb_get_hash_net() in seg6_make_flowlabel()

Since commit d58e468b1112 ("flow_dissector: implements flow dissector
BPF hook") __skb_flow_dissect() needs a net pointer, either from
skb->dev, skb->sk, or since commit 3cbf4ffba5ee ("net: plumb network
namespace into __skb_flow_dissect") a caller provided pointer.

syzbot was able to reach seg6_make_flowlabel() with an skb having
neither skb->dev nor skb->sk set: a TIPC UDP bearer sends a discovery
message through an IPv4 route using seg6 encap, while
net.ipv6.seg6_flowlabel is set to 1.

seg6_make_flowlabel() already has a net pointer, use skb_get_hash_net().

WARNING: net/core/flow_dissector.c:1131 at __skb_flow_dissect+0x910/0x5368 net/core/flow_dissector.c:1126, CPU#0: syz.0.17/4930
Call trace:
  __skb_flow_dissect+0x910/0x5368 net/core/flow_dissector.c:1126 (P)
  __skb_get_hash_net+0xe0/0x29c net/core/flow_dissector.c:1903
  skb_get_hash include/linux/skbuff.h:1663 [inline]
  seg6_make_flowlabel+0xcc/0x1ec net/ipv6/seg6_iptunnel.c:132
  __seg6_do_srh_encap+0x320/0xbf4 net/ipv6/seg6_iptunnel.c:161
  seg6_do_srh+0x4b4/0xa44 net/ipv6/seg6_iptunnel.c:431
  seg6_output_core+0x164/0x688 net/ipv6/seg6_iptunnel.c:681
  seg6_output+0x44/0x1ac net/ipv6/seg6_iptunnel.c:744
  lwtunnel_output+0x3d0/0x664 net/core/lwtunnel.c:356
  dst_output include/net/dst.h:470 [inline]
  ip_local_out+0x110/0x148 net/ipv4/ip_output.c:131
  iptunnel_xmit+0x50c/0xd38 net/ipv4/ip_tunnel_core.c:97
  udp_tunnel_xmit_skb+0x220/0x348 net/ipv4/udp_tunnel_core.c:187
  tipc_udp_xmit+0x75c/0x9c0 net/tipc/udp_media.c:202
  tipc_udp_send_msg+0x214/0x374 net/tipc/udp_media.c:274
  tipc_bearer_xmit_skb+0x260/0x3b0 net/tipc/bearer.c:576
  tipc_enable_bearer net/tipc/bearer.c:366 [inline]
  __tipc_nl_bearer_enable+0xc90/0xfb0 net/tipc/bearer.c:1048
  tipc_nl_bearer_enable+0x2c/0x48 net/tipc/bearer.c:1057
  genl_family_rcv_msg_doit+0x1e4/0x2d4 net/netlink/genetlink.c:1114

## Affected

- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 4ab37e4f4a33c64d9e565dc8c4c3ed774f05c0e3`
- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 8fe3d6717f5536793727e60b7a0b7ec20c697def`
- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 53b21bc2df6e8ed538bceda93a5104a5fe6a8a84`
- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 086e8acb3a0e55f6d22d29fae2a4a3b1561bb766`
- `Linux >= d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9 < 8ec454dcd00ce3375119111c6394964455b36d0d`
- `Linux 4.20`

## Remediation

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