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Fencer Vulns
medium 4.0

CVE-2020-28588 json

An information disclosure vulnerability exists in the /proc/pid/syscall functionality of Linux Kernel 5.1 Stable and 5.4.66.

published 2021-05-10 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-20986

cvss
4.0
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits
0
none known

Summary

An information disclosure vulnerability exists in the /proc/pid/syscall functionality of Linux Kernel 5.1 Stable and 5.4.66. More specifically, this issue has been introduced in v5.1-rc4 (commit 631b7abacd02b88f4b0795c08b54ad4fc3e7c7c0) and is still present in v5.10-rc4, so it’s likely that all versions in between are affected. An attacker can read /proc/pid/syscall to trigger this vulnerability, which leads to the kernel leaking memory contents.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 5.9.15-1

debian advisories DEBIAN-CVE-2020-28588

  • linux Ubuntu 20.04 LTS 5.4.0-66.74
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1038.40
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1037.40
  • linux-gke Ubuntu 20.04 LTS 5.4.0-1036.38
  • linux-kvm Ubuntu 20.04 LTS 5.4.0-1033.34
  • linux-azure Ubuntu 20.04 LTS 5.4.0-1040.42
  • linux-gkeop Ubuntu 20.04 LTS 5.4.0-1010.11
  • linux-raspi Ubuntu 20.04 LTS 5.4.0-1029.32

ubuntu advisories UBUNTU-CVE-2020-28588

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-2020-28588 updated cvss 2.9

kernel: information leak in the syscall implementation on 32-bit systems

  • 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, +81 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

1.10% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • talosintelligence.com https://talosintelligence.com/vulnerability_reports/TALOS-2020-1211 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 4.0 CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/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

  • n/a Linux Kernel

Classification

Weakness
  • CWE-681 Incorrect Conversion between Numeric Types
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.