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Fencer Vulns
medium 5.5

CVE-2019-20812 json

An issue was discovered in the Linux kernel before 5.4.7.

published 2020-06-03 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-11349

cvss
5.5
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 38%
public exploits
0
none known

Summary

An issue was discovered in the Linux kernel before 5.4.7. The prb_calc_retire_blk_tmo() function in net/packet/af_packet.c can result in a denial of service (CPU consumption and soft lockup) in a certain failure case involving TPACKET_V3, aka CID-b43d1f9f7067.

Patch / fix

  • linux linux_kernel 5.4.7
  • linux Debian 14, Debian 13, Debian 12 5.4.8-1

debian advisories DEBIAN-CVE-2019-20812

  • linux Ubuntu 16.04 LTS 4.4.0-173.203
  • linux Ubuntu 18.04 LTS 4.15.0-88.88
  • linux-aws Ubuntu 16.04 LTS 4.4.0-1101.112
  • linux-aws Ubuntu 18.04 LTS 4.15.0-1060.62
  • linux-gcp Ubuntu 16.04 LTS 4.15.0-1055.59
  • linux-hwe Ubuntu 16.04 LTS 4.15.0-88.88~16.04.1
  • linux-hwe Ubuntu 18.04 LTS 5.3.0-40.32~18.04.1
  • linux-kvm Ubuntu 16.04 LTS 4.4.0-1065.72

ubuntu advisories UBUNTU-CVE-2019-20812

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 4.18.0-240.el8
  • perf RHEL 8 4.18.0-240.el8
  • bpftool RHEL 8 4.18.0-240.el8
  • kernel-core RHEL 8 4.18.0-240.el8
  • kernel-tools RHEL 8 4.18.0-240.el8
  • python3-perf RHEL 8 4.18.0-240.el8
  • kernel-modules RHEL 8 4.18.0-240.el8
  • kernel-zfcpdump RHEL 8 4.18.0-240.el8

red hat advisories RHSA-2020:4431

  • 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-2020:2152-1SUSE-SU-2020:2134-1SUSE-SU-2020:2105-1

  • 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 15.2 5.3.18-lp152.26.2
  • kernel-obs-qa openSUSE Leap 15.2 5.3.18-lp152.26.2
  • kernel-source openSUSE Leap 15.2 5.3.18-lp152.26.2
  • kernel-default openSUSE Leap 15.2 5.3.18-lp152.26.2

opensuse advisories openSUSE-SU-2021:0242-1openSUSE-SU-2020:0935-1openSUSE-SU-2020:0801-1

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-2019-20812 updated cvss 4.4

kernel: af_packet: TPACKET_V3: invalid timer timeout on error

  • Red Hat Enterprise Linux 5 kernel 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 Linux 7 perf, kernel, bpftool, kernel-rt, kernel-alt, python-perf, +9 more
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux 8 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +6 more
    affected: workaround, no fix available
  • Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-240.el8, kernel-debuginfo-common-aarch64 4.18.0-240.el8, kernel-debuginfo-common-ppc64le 4.18.0-240.el8 Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-240.el8, kernel 4.18.0-240.el8, bpftool 4.18.0-240.el8, kernel-core 4.18.0-240.el8, kernel-tools 4.18.0-240.el8, python3-perf 4.18.0-240.el8, +15 more
    fixed: vendor fix RHSA-2020:4431

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

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
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.