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Fencer Vulns
medium 5.5

CVE-2020-10766 json

A logic bug flaw was found in Linux kernel before 5.8-rc1 in the implementation of SSBD.

published 2020-09-15 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-3181

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

A logic bug flaw was found in Linux kernel before 5.8-rc1 in the implementation of SSBD. A bug in the logic handling allows an attacker with a local account to disable SSBD protection during a context switch when additional speculative execution mitigations are in place. This issue was introduced when the per task/process conditional STIPB switching was added on top of the existing SSBD switching. The highest threat from this vulnerability is to confidentiality.

Patch / fix

  • linux linux_kernel 5.8.0
  • linux Debian 14, Debian 13, Debian 12 5.7.6-1

debian advisories DEBIAN-CVE-2020-10766

  • linux Ubuntu 16.04 LTS 4.4.0-186.216
  • linux Ubuntu 18.04 LTS 4.15.0-115.116
  • linux Ubuntu 20.04 LTS 5.4.0-45.49
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1111.123
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1080.84
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1022.22
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1081.92~16.04.1
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1022.22

ubuntu advisories UBUNTU-CVE-2020-10766

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

  • kpatch-patch-4_18_0-193 RHEL 8 1-5.el8
  • kpatch-patch-4_18_0-193_1_2 RHEL 8 1-3.el8_2
  • kpatch-patch-4_18_0-193_6_3 RHEL 8 1-2.el8_2
  • kernel-rt RHEL 8 4.18.0-193.13.2.rt13.65.el8_2
  • kernel-rt-kvm RHEL 8 4.18.0-193.13.2.rt13.65.el8_2
  • kernel-rt-core RHEL 8 4.18.0-193.13.2.rt13.65.el8_2
  • kernel-rt-modules RHEL 8 4.18.0-193.13.2.rt13.65.el8_2
  • kernel-rt-debug-kvm RHEL 8 4.18.0-193.13.2.rt13.65.el8_2

red hat advisories RHSA-2020:3222RHSA-2020:3297RHSA-2020:3073RHSA-2020:3041RHSA-2020:3016RHSA-2020:3010

  • kernel-rt Real Time Module 15 SP1 4.12.14-14.28.1
  • kernel-syms-rt Real Time Module 15 SP1 4.12.14-14.28.1
  • kernel-rt_debug Real Time Module 15 SP1 4.12.14-14.28.1
  • kernel-source-rt Real Time Module 15 SP1 4.12.14-14.28.1
  • kernel-rt SLE Real Time 12 SP5 4.12.14-10.13.1
  • kernel-syms-rt SLE Real Time 12 SP5 4.12.14-10.13.1
  • kernel-rt_debug SLE Real Time 12 SP5 4.12.14-10.13.1
  • kernel-source-rt SLE Real Time 12 SP5 4.12.14-10.13.1

suse advisories SUSE-SU-2020:2487-1SUSE-SU-2020:2478-1SUSE-SU-2020:2156-1SUSE-SU-2020:2134-1SUSE-SU-2020:2121-1SUSE-SU-2020:2107-1

  • kernel-source openSUSE Tumbleweed 5.14.6-1.4
  • kernel-source openSUSE Tumbleweed 6.6.17-1.1
  • 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-lp151.28.59.1
  • kernel-obs-qa openSUSE Leap 15.1 4.12.14-lp151.28.59.1

opensuse advisories openSUSE-SU-2024:10728-1openSUSE-SU-2024:13704-1openSUSE-SU-2021:0242-1openSUSE-SU-2020:1153-1openSUSE-SU-2020:0935-1

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-2020-10766 updated cvss 5.5

kernel: Rogue cross-process SSBD shutdown. Linux scheduler logical bug allows an attacker to turn off the SSBD protection.

  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-193.13.2.el8_2, kernel-debuginfo-common-aarch64 4.18.0-193.13.2.el8_2, kernel-debuginfo-common-ppc64le 4.18.0-193.13.2.el8_2
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2020:3010
  • Red Hat CodeReady Linux Builder EUS (v. 8.1) kernel-debuginfo-common-x86_64 4.18.0-147.24.2.el8_1, kernel-debuginfo-common-aarch64 4.18.0-147.24.2.el8_1, kernel-debuginfo-common-ppc64le 4.18.0-147.24.2.el8_1
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2020:3222
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-193.13.2.el8_2, kernel 4.18.0-193.13.2.el8_2, bpftool 4.18.0-193.13.2.el8_2, kpatch-patch-4_18_0-193 1-5.el8, kernel-core 4.18.0-193.13.2.el8_2, kernel-tools 4.18.0-193.13.2.el8_2, +18 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2020:3010
  • Red Hat Enterprise Linux BaseOS E4S (v. 8.0) perf 4.18.0-80.27.1.el8_0, kernel 4.18.0-80.27.1.el8_0, bpftool 4.18.0-80.27.1.el8_0, kernel-core 4.18.0-80.27.1.el8_0, kernel-tools 4.18.0-80.27.1.el8_0, python3-perf 4.18.0-80.27.1.el8_0, +9 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2020:3041
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.1) perf 4.18.0-147.24.2.el8_1, kernel 4.18.0-147.24.2.el8_1, bpftool 4.18.0-147.24.2.el8_1, kpatch-patch-4_18_0-147 1-16.el8, kernel-core 4.18.0-147.24.2.el8_1, kernel-tools 4.18.0-147.24.2.el8_1, +23 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2020:3222
  • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-core 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-modules 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-debug-core 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-debug-modules 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-modules-extra 4.18.0-193.13.2.rt13.65.el8_2, +2 more Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-kvm 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-core 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-modules 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-debug-kvm 4.18.0-193.13.2.rt13.65.el8_2, kernel-rt-debug-core 4.18.0-193.13.2.rt13.65.el8_2, +4 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update as soon as possible.” RHSA-2020:3016
  • 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 Linux 7 perf, kernel, bpftool, kernel-rt, kernel-alt, python-perf, +9 more Red Hat Enterprise Linux BaseOS E4S (v. 8.0) kernel-headers 4.18.0-80.27.1.el8_0, kernel-cross-headers 4.18.0-80.27.1.el8_0 Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    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

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N

Affected products

  • Linux Kernel kernel

Classification

Weakness
  • CWE-440 Expected Behavior Violation
Technology feeds

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.