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Fencer Vulns
medium 5.7

CVE-2020-27825 json

A use-after-free flaw was found in kernel/trace/ring_buffer.c in Linux kernel (before 5.10-rc1).

published 2020-12-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-20325

cvss
5.7
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

A use-after-free flaw was found in kernel/trace/ring_buffer.c in Linux kernel (before 5.10-rc1). There was a race problem in trace_open and resize of cpu buffer running parallely on different cpus, may cause a denial of service problem (DOS). This flaw could even allow a local attacker with special user privilege to a kernel information leak threat.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.9.6-1

debian advisories DEBIAN-CVE-2020-27825

  • kernel-syms SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLES 15 SP2-BCL +6 more 5.3.18-24.99.1
  • kernel-source SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLES 15 SP2-BCL +6 more 5.3.18-24.99.1
  • kernel-default SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLES 15 SP2-BCL +9 more 5.3.18-24.99.1
  • kernel-preempt SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLES 15 SP2-BCL +6 more 5.3.18-24.99.1
  • kernel-obs-build SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS +3 more 5.3.18-24.99.1
  • kernel-default-base SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLES 15 SP2-BCL +7 more 5.3.18-24.99.1.9.46.1
  • kernel-syms SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.4.180-94.138.1
  • kernel-source SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.4.180-94.138.1

suse advisories SUSE-SU-2022:0197-1SUSE-SU-2021:0452-1SUSE-SU-2021:0438-1SUSE-SU-2021:0437-1SUSE-SU-2021:0434-1SUSE-SU-2021:0133-1

  • 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-lp151.28.91.1
  • kernel-obs-qa openSUSE Leap 15.1 4.12.14-lp151.28.91.1
  • kernel-source openSUSE Leap 15.1 4.12.14-lp151.28.91.1
  • kernel-default openSUSE Leap 15.1 4.12.14-lp151.28.91.1

opensuse advisories openSUSE-SU-2021:0242-1openSUSE-SU-2021:0075-1openSUSE-SU-2021:0060-1

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-2020-27825 updated cvss 6.7

kernel: use-after-free in the ftrace ring buffer resizing logic due to a race condition

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux 5 kernel 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
    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

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.7 CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:H
NVD 2.0 5.4 AV:L/AC:M/Au:N/C:P/I:N/A:C

Affected products

  • n/a kernel

Classification

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