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Fencer Vulns
medium 6.5

CVE-2020-29373 json

An issue was discovered in fs/io_uring.c in the Linux kernel before 5.6.

published 2020-11-28 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-21746

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

An issue was discovered in fs/io_uring.c in the Linux kernel before 5.6. It unsafely handles the root directory during path lookups, and thus a process inside a mount namespace can escape to unintended filesystem locations, aka CID-ff002b30181d.

Patch / fix

  • linux linux_kernel 5.6
  • linux Debian 14, Debian 13, Debian 12 5.6.7-1

debian advisories DEBIAN-CVE-2020-29373

  • linux-gke-5.3 Ubuntu 18.04 LTS 5.3.0-1018.19~18.04.1
  • linux-raspi2-5.3 Ubuntu 18.04 LTS 5.3.0-1023.25~18.04.1

ubuntu advisories UBUNTU-CVE-2020-29373

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-syms SLE Module for Development Tools 15 SP2 5.3.18-24.46.1
  • kernel-source SLE Module for Development Tools 15 SP2, SLE Module for Basesystem 15 SP2 5.3.18-24.46.1
  • kernel-default SLE Workstation Extension 15 SP2, SLE Module for Legacy 15 SP2, SLE Module for Basesystem 15 SP2 +2 more 5.3.18-24.46.1
  • kernel-preempt SLE Module for Development Tools 15 SP2, SLE Module for Basesystem 15 SP2 5.3.18-24.46.1
  • kernel-obs-build SLE Module for Development Tools 15 SP2 5.3.18-24.46.1
  • kernel-default-base SLE Module for Basesystem 15 SP2 5.3.18-24.46.1.9.19.1
  • kernel-rt Real Time Module 15 SP2 5.3.18-22.1
  • kernel-syms-rt Real Time Module 15 SP2 5.3.18-22.1

suse advisories SUSE-SU-2021:0869-1SUSE-SU-2021:0367-1SUSE-SU-2021:0362-1SUSE-SU-2021:0359-1SUSE-SU-2021:0117-1SUSE-SU-2021:0108-1

  • 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-lp152.60.1
  • kernel-obs-qa openSUSE Leap 15.2 5.3.18-lp152.60.1
  • kernel-source openSUSE Leap 15.2 5.3.18-lp152.60.1
  • kernel-default openSUSE Leap 15.2 5.3.18-lp152.60.1

opensuse advisories openSUSE-SU-2021:0242-1openSUSE-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-2020-29373 updated cvss 0.0

kernel: Insecure handling of root directory for path lookups via io_uring

  • 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 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise MRG 2 kernel
    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

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugs.chromium.org https://bugs.chromium.org/p/project-zero/issues/detail?id=2011 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
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.