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Fencer Intel
high 7.5

CVE-2020-1749 json

A flaw was found in the Linux kernel's implementation of some networking protocols in IPsec, such as VXLAN and GENEVE tunnels over IPv6.

published 6y ago modified 4mo ago also EUVD-2020-12580

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

A flaw was found in the Linux kernel's implementation of some networking protocols in IPsec, such as VXLAN and GENEVE tunnels over IPv6. When an encrypted tunnel is created between two hosts, the kernel isn't correctly routing tunneled data over the encrypted link; rather sending the data unencrypted. This would allow anyone in between the two endpoints to read the traffic unencrypted. The main threat from this vulnerability is to data confidentiality.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.4.6-1

debian advisories DEBIAN-CVE-2020-1749

  • linux Ubuntu 16.04 LTS 4.4.0-184.214
  • linux Ubuntu 18.04 LTS 4.15.0-106.107
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1109.120
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1073.77
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1077.87~16.04.1
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-106.107~16.04.1
  • linux-hwe Ubuntu 18.04 LTS 5.3.0-40.32~18.04.1
  • linux-kvm Ubuntu 16.04 LTS 4.4.0-1075.82

ubuntu advisories UBUNTU-CVE-2020-1749

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 7 3.10.0-1160.el7
  • perf RHEL 7 3.10.0-1160.el7
  • bpftool RHEL 7 3.10.0-1160.el7
  • python-perf RHEL 7 3.10.0-1160.el7
  • kernel-kdump RHEL 7 3.10.0-1160.el7
  • kernel-tools RHEL 7 3.10.0-1160.el7
  • kernel-tools-libs RHEL 7 3.10.0-1160.el7
  • kernel-bootwrapper RHEL 7 3.10.0-1160.el7

red hat advisories RHSA-2020:4060RHSA-2020:4062RHSA-2020:1567RHSA-2020:1769RHSA-2021:0354

  • kernel-syms SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +3 more 4.4.180-94.144.1
  • kernel-source SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +3 more 4.4.180-94.144.1
  • kernel-default SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.4.180-94.144.1
  • kgraft-patch-SLE12-SP3_Update_39 SLES for SAP 12 SP3, SLES 12 SP3-LTSS, OpenStack Cloud Crowbar 8 +2 more 1-4.3.1
  • kernel-syms SLES 12 SP2-BCL 4.4.121-92.155.1
  • kernel-source SLES 12 SP2-BCL 4.4.121-92.155.1
  • kernel-default SLES 12 SP2-BCL 4.4.121-92.155.1
  • kernel-rt Real Time Module 15 SP1 4.12.14-14.36.1

suse advisories SUSE-SU-2021:1623-1SUSE-SU-2021:1617-1SUSE-SU-2021:1074-1SUSE-SU-2021:0835-1SUSE-SU-2020:3656-1SUSE-SU-2020:3648-1

  • kernel-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
  • kernel-syms-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
  • kernel-rt_debug openSUSE Leap 15.2 5.3.18-lp152.3.5.1
  • kernel-source-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
  • kernel-syms openSUSE Leap 15.1 4.12.14-lp151.28.63.1
  • kernel-obs-qa openSUSE Leap 15.1 4.12.14-lp151.28.63.1
  • kernel-source openSUSE Leap 15.1 4.12.14-lp151.28.63.1
  • kernel-default openSUSE Leap 15.1 4.12.14-lp151.28.63.1

opensuse advisories openSUSE-SU-2021:0242-1openSUSE-SU-2020:1325-1

Is CVE-2020-1749 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-1749 updated cvss 7.5

kernel: some ipv6 protocols not encrypted over ipsec tunnel

  • Red Hat Enterprise Linux 5 kernel Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    affected: workaround, no fix planned “Disabling the IPV6 protocol may be a suitable workaround for systems that do not require the protocol to function correctly, however, if IPV6 is not in use this flaw will not be triggered.”
  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-193.el8, kernel-debuginfo-common-aarch64 4.18.0-193.el8, kernel-debuginfo-common-ppc64le 4.18.0-193.el8 Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-193.el8, kernel 4.18.0-193.el8, bpftool 4.18.0-193.el8, kernel-core 4.18.0-193.el8, kernel-tools 4.18.0-193.el8, python3-perf 4.18.0-193.el8, +15 more
    fixed: vendor fix “Disabling the IPV6 protocol may be a suitable workaround for systems that do not require the protocol to function correctly, however, if IPV6 is not in use this flaw will not be triggered.” RHSA-2020:1769
  • Red Hat Enterprise Linux Client (v. 7) perf 3.10.0-1160.el7, kernel 3.10.0-1160.el7, bpftool 3.10.0-1160.el7, python-perf 3.10.0-1160.el7, kernel-tools 3.10.0-1160.el7, kernel-tools-libs 3.10.0-1160.el7, +2 more Red Hat Enterprise Linux Client Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.el7 Red Hat Enterprise Linux ComputeNode (v. 7) perf 3.10.0-1160.el7, kernel 3.10.0-1160.el7, bpftool 3.10.0-1160.el7, python-perf 3.10.0-1160.el7, kernel-tools 3.10.0-1160.el7, kernel-tools-libs 3.10.0-1160.el7, +2 more Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.el7
    fixed: vendor fix “Disabling the IPV6 protocol may be a suitable workaround for systems that do not require the protocol to function correctly, however, if IPV6 is not in use this flaw will not be triggered.” RHSA-2020:4060
  • Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) perf 4.14.0-115.35.1.el7a, kernel 4.14.0-115.35.1.el7a, kernel-alt 4.14.0-115.35.1.el7a, python-perf 4.14.0-115.35.1.el7a, kernel-tools 4.14.0-115.35.1.el7a, kernel-tools-libs 4.14.0-115.35.1.el7a, +3 more Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) kernel-debuginfo-common-ppc64le 4.14.0-115.35.1.el7a
    fixed: vendor fix “Disabling the IPV6 protocol may be a suitable workaround for systems that do not require the protocol to function correctly, however, if IPV6 is not in use this flaw will not be triggered.” RHSA-2021:0354
  • Red Hat Enterprise Linux for Real Time (v. 7) kernel-rt 3.10.0-1160.rt56.1131.el7, kernel-rt-trace 3.10.0-1160.rt56.1131.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.rt56.1131.el7 Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt 3.10.0-1160.rt56.1131.el7, kernel-rt-kvm 3.10.0-1160.rt56.1131.el7, kernel-rt-trace 3.10.0-1160.rt56.1131.el7, kernel-rt-debug-kvm 3.10.0-1160.rt56.1131.el7, kernel-rt-trace-kvm 3.10.0-1160.rt56.1131.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1160.rt56.1131.el7
    fixed: vendor fix “Disabling the IPV6 protocol may be a suitable workaround for systems that do not require the protocol to function correctly, however, if IPV6 is not in use this flaw will not be triggered.” RHSA-2020:4062
  • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-193.rt13.51.el8, kernel-rt-core 4.18.0-193.rt13.51.el8, kernel-rt-modules 4.18.0-193.rt13.51.el8, kernel-rt-debug-core 4.18.0-193.rt13.51.el8, kernel-rt-debug-modules 4.18.0-193.rt13.51.el8, kernel-rt-modules-extra 4.18.0-193.rt13.51.el8, +2 more Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-193.rt13.51.el8, kernel-rt-kvm 4.18.0-193.rt13.51.el8, kernel-rt-core 4.18.0-193.rt13.51.el8, kernel-rt-modules 4.18.0-193.rt13.51.el8, kernel-rt-debug-kvm 4.18.0-193.rt13.51.el8, kernel-rt-debug-core 4.18.0-193.rt13.51.el8, +4 more
    fixed: vendor fix “Disabling the IPV6 protocol may be a suitable workaround for systems that do not require the protocol to function correctly, however, if IPV6 is not in use this flaw will not be triggered.” RHSA-2020:1567
  • Red Hat Enterprise Linux Server (v. 7) perf 3.10.0-1160.el7, kernel 3.10.0-1160.el7, bpftool 3.10.0-1160.el7, python-perf 3.10.0-1160.el7, kernel-kdump 3.10.0-1160.el7, kernel-tools 3.10.0-1160.el7, +7 more Red Hat Enterprise Linux Server Optional (v. 7) kernel-debuginfo-common-ppc64 3.10.0-1160.el7, kernel-debuginfo-common-x86_64 3.10.0-1160.el7, kernel-debuginfo-common-ppc64le 3.10.0-1160.el7 Red Hat Enterprise Linux Workstation (v. 7) perf 3.10.0-1160.el7, kernel 3.10.0-1160.el7, bpftool 3.10.0-1160.el7, python-perf 3.10.0-1160.el7, kernel-tools 3.10.0-1160.el7, kernel-tools-libs 3.10.0-1160.el7, +2 more Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1160.el7
    fixed: vendor fix “Disabling the IPV6 protocol may be a suitable workaround for systems that do not require the protocol to function correctly, however, if IPV6 is not in use this flaw will not be triggered.” RHSA-2020:4060

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.24% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Affected products

  • Linux Kernel kernel

Classification

Weakness
  • CWE-319 Cleartext Transmission of Sensitive Information
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.