UBUNTU-CVE-2021-47515

Advisory lineage Upstream: 1 Downstream: 0
Upstream
CVE-2021-47515
Published: 24 May 2024, 15:15
Last modified:03 Jun 2026, 13:34

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
3.1 (osv_ubuntu)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

24 May 2024, 15:15
Published
Vulnerability first disclosed
03 Jun 2026, 13:34
Last Modified
Vulnerability information updated

Description

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 Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Systems

  • ubuntu•linux

    < 4.15.0-169.177 | < 5.4.0-100.113

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    < 4.15.0-1121.129 | < 5.4.0-1066.69

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    < 5.4.0-1066.69~18.04.1

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-fips

    < 4.15.0-2061.63 | < 5.4.0-1069.73+fips2 | all

  • ubuntu•linux-aws-hwe

    < 4.15.0-1120.128~16.04.1

  • ubuntu•linux-azure

    < 4.15.0-1131.144~14.04.1 | < 4.15.0-1131.144~16.04.1 | all | < 5.4.0-1070.73

  • ubuntu•linux-azure-4.15

    < 4.15.0-1131.144

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    < 5.4.0-1070.73~18.04.1

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-fips

    < 4.15.0-2043.47 | < 5.4.0-1073.76+fips1 | all

  • ubuntu•linux-bluefield

    < 5.4.0-1028.31 | all

  • ubuntu•linux-fips

    < 4.15.0-1078.87 | all | < 5.4.0-1043.49

  • ubuntu•linux-gcp

    < 4.15.0-1116.130~16.04.1 | all | < 5.4.0-1065.69

  • ubuntu•linux-gcp-4.15

    < 4.15.0-1116.130

  • ubuntu•linux-gcp-5.11

    all

  • ubuntu•linux-gcp-5.13

    all

  • ubuntu•linux-gcp-5.19

    all

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.4

    < 5.4.0-1065.69~18.04.1

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-6.2

    all

  • ubuntu•linux-gcp-fips

    < 4.15.0-2026.28 | < 5.4.0-1067.71~20.04.1 | all

  • ubuntu•linux-gke

    all

  • ubuntu•linux-gke-4.15

    all

  • ubuntu•linux-gke-5.15

    all

  • ubuntu•linux-gke-5.4

    all

  • ubuntu•linux-gkeop

    < 5.4.0-1034.35

  • ubuntu•linux-gkeop-5.4

    all

  • ubuntu•linux-hwe

    < 4.15.0-169.177~16.04.1 | all

  • ubuntu•linux-hwe-5.11

    all

  • ubuntu•linux-hwe-5.13

    all

  • ubuntu•linux-hwe-5.19

    all

  • ubuntu•linux-hwe-5.4

    < 5.4.0-100.113~18.04.1

Showing first 50 affected entries in server-rendered view.

References (9)