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Fencer Intel
high 7.0

CVE-2020-29368 json

An issue was discovered in __split_huge_pmd in mm/huge_memory.c in the Linux kernel before 5.7.5.

published 5y ago modified 4mo ago also EUVD-2020-21741

cvss
7.0
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

An issue was discovered in __split_huge_pmd in mm/huge_memory.c in the Linux kernel before 5.7.5. The copy-on-write implementation can grant unintended write access because of a race condition in a THP mapcount check, aka CID-c444eb564fb1.

Patch / fix

  • linux linux_kernel 4.9.228, 4.14.185, 4.19.129, 5.4.48, 5.7.5
  • linux Debian 14, Debian 13, Debian 12 5.7.6-1

debian advisories DEBIAN-CVE-2020-29368

  • linux Ubuntu 18.04 LTS 4.15.0-115.116
  • linux Ubuntu 20.04 LTS 5.4.0-45.49
  • 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
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-115.116~16.04.1
  • linux-kvm Ubuntu 18.04 LTS 4.15.0-1072.73

ubuntu advisories UBUNTU-CVE-2020-29368

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 8 4.18.0-348.el8
  • perf RHEL 8 4.18.0-348.el8
  • bpftool RHEL 8 4.18.0-348.el8
  • kernel-core RHEL 8 4.18.0-348.el8
  • kernel-tools RHEL 8 4.18.0-348.el8
  • python3-perf RHEL 8 4.18.0-348.el8
  • kernel-modules RHEL 8 4.18.0-348.el8
  • kernel-zfcpdump RHEL 8 4.18.0-348.el8

red hat advisories RHSA-2021:4356RHSA-2022:5220RHSA-2022:5224RHSA-2022:5626RHSA-2022:5633RHSA-2021:4140

  • kernel-syms SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.66.2
  • kernel-source SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.66.2
  • kernel-default SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +2 more 4.12.14-122.66.2
  • kernel-obs-build SLE Software Development Kit 12 SP5 4.12.14-122.66.2
  • kernel-rt SLE Real Time 12 SP5 4.12.14-10.37.1
  • kernel-syms-rt SLE Real Time 12 SP5 4.12.14-10.37.1
  • kernel-rt_debug SLE Real Time 12 SP5 4.12.14-10.37.1
  • kernel-source-rt SLE Real Time 12 SP5 4.12.14-10.37.1

suse advisories SUSE-SU-2021:1210-1SUSE-SU-2021:1176-1SUSE-SU-2021:1175-1SUSE-SU-2021:1046-1SUSE-SU-2021:0869-1SUSE-SU-2021:0868-1

  • kernel-syms openSUSE Leap 15.2 5.3.18-lp152.66.2
  • kernel-obs-qa openSUSE Leap 15.2 5.3.18-lp152.66.2
  • kernel-source openSUSE Leap 15.2 5.3.18-lp152.66.2
  • kernel-default openSUSE Leap 15.2 5.3.18-lp152.66.2
  • kernel-preempt openSUSE Leap 15.2 5.3.18-lp152.66.2
  • kernel-kvmsmall openSUSE Leap 15.2 5.3.18-lp152.66.2
  • kernel-obs-build openSUSE Leap 15.2 5.3.18-lp152.66.2
  • kernel-default-base openSUSE Leap 15.2 5.3.18-lp152.66.2.lp152.8.23.2

opensuse advisories openSUSE-SU-2021:0393-1

Is CVE-2020-29368 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.

Check with Fencer

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-2020-29368 updated cvss 7.0

kernel: the copy-on-write implementation can grant unintended write access because of a race condition in a THP mapcount check

  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-348.el8, kernel-debuginfo-common-aarch64 4.18.0-348.el8, kernel-debuginfo-common-ppc64le 4.18.0-348.el8
    fixed: vendor fix RHSA-2021:4356
  • Red Hat CodeReady Linux Builder EUS (v. 8.2) kernel-debuginfo-common-x86_64 4.18.0-193.87.1.el8_2, kernel-debuginfo-common-aarch64 4.18.0-193.87.1.el8_2, kernel-debuginfo-common-ppc64le 4.18.0-193.87.1.el8_2
    fixed: vendor fix RHSA-2022:5220
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-348.el8, kernel 4.18.0-348.el8, bpftool 4.18.0-348.el8, kernel-core 4.18.0-348.el8, kernel-tools 4.18.0-348.el8, python3-perf 4.18.0-348.el8, +15 more
    fixed: vendor fix RHSA-2021:4356
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.2) perf 4.18.0-193.87.1.el8_2, kernel 4.18.0-193.87.1.el8_2, bpftool 4.18.0-193.87.1.el8_2, kernel-core 4.18.0-193.87.1.el8_2, kernel-tools 4.18.0-193.87.1.el8_2, python3-perf 4.18.0-193.87.1.el8_2, +15 more
    fixed: vendor fix RHSA-2022:5220
  • Red Hat Enterprise Linux BaseOS EUS (v.8.4) perf 4.18.0-305.57.1.el8_4, kernel 4.18.0-305.57.1.el8_4, bpftool 4.18.0-305.57.1.el8_4, kernel-core 4.18.0-305.57.1.el8_4, kernel-tools 4.18.0-305.57.1.el8_4, python3-perf 4.18.0-305.57.1.el8_4, +15 more Red Hat Enterprise Linux CRB EUS (v.8.4) kernel-debuginfo-common-x86_64 4.18.0-305.57.1.el8_4, kernel-debuginfo-common-aarch64 4.18.0-305.57.1.el8_4, kernel-debuginfo-common-ppc64le 4.18.0-305.57.1.el8_4
    fixed: vendor fix RHSA-2022:5626
  • Red Hat Enterprise Linux NFV EUS (v.8.4) kernel-rt 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-kvm 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-core 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-modules 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-debug-kvm 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-debug-core 4.18.0-305.57.1.rt7.129.el8_4, +4 more
    fixed: vendor fix RHSA-2022:5633
  • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-348.rt7.130.el8, kernel-rt-core 4.18.0-348.rt7.130.el8, kernel-rt-modules 4.18.0-348.rt7.130.el8, kernel-rt-debug-core 4.18.0-348.rt7.130.el8, kernel-rt-debug-modules 4.18.0-348.rt7.130.el8, kernel-rt-modules-extra 4.18.0-348.rt7.130.el8, +2 more
    fixed: vendor fix RHSA-2021:4140
  • Red Hat Enterprise Linux Real Time EUS (v. 8.2) kernel-rt 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-core 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-modules 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-debug-core 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-debug-modules 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-modules-extra 4.18.0-193.87.1.rt13.137.el8_2, +2 more
    fixed: vendor fix RHSA-2022:5224
show 4 more
  • Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-348.rt7.130.el8, kernel-rt-kvm 4.18.0-348.rt7.130.el8, kernel-rt-core 4.18.0-348.rt7.130.el8, kernel-rt-modules 4.18.0-348.rt7.130.el8, kernel-rt-debug-kvm 4.18.0-348.rt7.130.el8, kernel-rt-debug-core 4.18.0-348.rt7.130.el8, +4 more
    fixed: vendor fix RHSA-2021:4140
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2) kernel-rt 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-kvm 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-core 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-modules 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-debug-kvm 4.18.0-193.87.1.rt13.137.el8_2, kernel-rt-debug-core 4.18.0-193.87.1.rt13.137.el8_2, +4 more
    fixed: vendor fix RHSA-2022:5224
  • Red Hat Enterprise Linux RT EUS (v.8.4) kernel-rt 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-core 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-modules 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-debug-core 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-debug-modules 4.18.0-305.57.1.rt7.129.el8_4, kernel-rt-modules-extra 4.18.0-305.57.1.rt7.129.el8_4, +2 more
    fixed: vendor fix RHSA-2022:5633
  • 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, python-perf, kernel-kdump, +8 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

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugs.chromium.org https://bugs.chromium.org/p/project-zero/issues/detail?id=2045 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.9 AV:L/AC:M/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
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.