In the Linux kernel, the following vulnerability has been resolved:
seg6: fix the iif in the IPv6 socket control block
When an IPv4 packet is received, the ip_rcv_core(...) sets the receiving interface index into the IPv4 socket control block (v5.16-rc4, net/ipv4/ip_input.c line 510):
IPCB(skb)->iif = skb->skb_iif;
If that IPv4 packet is meant to be encapsulated in an outer IPv6+SRH header, the seg6_do_srh_encap(...) performs the required encapsulation. In this case, the seg6_do_srh_encap function clears the IPv6 socket control block (v5.16-rc4 net/ipv6/seg6_iptunnel.c line 163):
memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
The memset(...) was introduced in commit ef489749aae5 ("ipv6: sr: clear IP6CB(skb) on SRH ip4ip6 encapsulation") a long time ago (2019-01-29).
Since the IPv6 socket control block and the IPv4 socket control block share the same memory area (skb->cb), the receiving interface index info is lost (IP6CB(skb)->iif is set to zero).
As a side effect, that condition triggers a NULL pointer dereference if commit 0857d6f8c759 ("ipv6: When forwarding count rx stats on the orig netdev") is applied.
To fix that issue, we set the IP6CB(skb)->iif with the index of the receiving interface once again.
CVSS Details
- CVSS 3.1 Base Score: 7.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-debuginfo-common-aarch64Upgrade bpftoolUpgrade kernel-debuginfoUpgrade kernel-tools-debuginfoUpgrade kernel-develUpgrade kernel-livepatch-5.10.93-87.444Upgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernelUpgrade perf-debuginfoUpgrade kernel-toolsUpgrade kernel-tools-develUpgrade python-perfUpgrade python-perf-debuginfoUpgrade perfUpgrade kernel-livepatch-4.14.262-200.489Upgrade kernel-headers | May 21, 2025 | May 24, 2024 |
| Debian | — | Upgrade linux | Jul 30, 2024 | May 24, 2024 |
| Redhat_linux | — | No solution exists | Jul 23, 2026 | May 24, 2024 |
| Suse | — | Upgrade kernel-rt_debug-vdsoUpgrade kernel-azure-vdsoUpgrade kernel-rt-livepatch-develUpgrade kernel-source-rtUpgrade kernel-azure-extraUpgrade kernel-syms-rtUpgrade kernel-azureUpgrade kernel-rt-extraUpgrade kernel-azure-optionalUpgrade kernel-rt_debug-livepatch-develUpgrade kselftests-kmp-azureUpgrade kernel-rtUpgrade kernel-azure-develUpgrade dlm-kmp-rtUpgrade kernel-syms-azureUpgrade gfs2-kmp-azureUpgrade kernel-rt_debug-develUpgrade reiserfs-kmp-rtUpgrade kernel-rt-optionalUpgrade kernel-rt-vdsoUpgrade kernel-rt_debugUpgrade kernel-source-azureUpgrade kernel-azure-livepatch-develUpgrade dlm-kmp-azureUpgrade ocfs2-kmp-azureUpgrade cluster-md-kmp-rtUpgrade kernel-devel-azureUpgrade gfs2-kmp-rtUpgrade ocfs2-kmp-rtUpgrade reiserfs-kmp-azureUpgrade cluster-md-kmp-azureUpgrade kselftests-kmp-rtUpgrade kernel-rt-develUpgrade kernel-devel-rtUpgrade kernel-rt-livepatch | Aug 9, 2024 | May 24, 2024 |
| Ubuntu | — | Upgrade linux-ibmUpgrade linux-bluefieldUpgrade linux-gcp-4.15Upgrade linux-raspi-5.4Upgrade linux-azureUpgrade linux-gcp-5.4Upgrade linux-hwe-5.4Upgrade linux-awsUpgrade linux-gcp-fipsUpgrade linux-aws-fipsUpgrade linux-azure-4.15Upgrade linuxUpgrade linux-azure-5.4Upgrade linux-kvmUpgrade linux-hweUpgrade linux-gcpUpgrade linux-aws-5.4Upgrade linux-oracleUpgrade linux-raspiUpgrade linux-oracle-5.4Upgrade linux-azure-fipsUpgrade linux-fipsUpgrade linux-ibm-5.4Upgrade linux-gkeopUpgrade linux-aws-hwe | Nov 19, 2024 | May 24, 2024 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | May 24, 2024 |
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