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Fencer Vulns
medium 6.7

CVE-2020-27066 json

In xfrm6_tunnel_free_spi of net/ipv6/xfrm6_tunnel.c, there is a possible use after free due to improper locking.

published 2020-12-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-19590

cvss
6.7
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

In xfrm6_tunnel_free_spi of net/ipv6/xfrm6_tunnel.c, there is a possible use after free due to improper locking. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-168043318

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.5.17-1

debian advisories DEBIAN-CVE-2020-27066

  • linux Ubuntu 16.04 LTS 4.4.0-179.209
  • linux Ubuntu 18.04 LTS 4.15.0-99.100
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1107.118
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1066.70
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1061.65
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-99.100~16.04.1
  • linux-kvm Ubuntu 16.04 LTS 4.4.0-1071.78
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1059.60

ubuntu advisories UBUNTU-CVE-2020-27066

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

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-2020-27066 updated cvss 6.7

kernel: use after free in xfrm6_tunnel_free_spi of net/ipv6/xfrm6_tunnel.c leads to local escalation of privilege

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, kernel-alt, python-perf, +9 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    not affected: vulnerable code not present

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

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.7 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • n/a Android

Classification

Weakness

References

Sources

Fencer Vulns 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.