CVE-2021-35939

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-08-26 · updated 2026-06-17
Weakness: CWE-59

Description

It was found that the fix for CVE-2017-7500 and CVE-2017-7501 was incomplete: the check was only implemented for the parent directory of the file to be created. A local unprivileged user who owns another ancestor directory could potentially use this flaw to gain root privileges. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Affected products

Red Hat Enterprise Linux: 8.0
RPM: before 4.18 — fixed in 4.18

How to fix

Upgrade to a fixed version: RPM 4.18. Check the vendor advisory for mitigations.

References

https://access.redhat.com/security/cve/CVE-2021-35939
https://bugzilla.redhat.com/show_bug.cgi?id=1964129
https://github.com/rpm-software-management/rpm/commit/96ec957e281220f8e137a2d5eb23b83a6377d556
https://github.com/rpm-software-management/rpm/pull/1919
https://rpm.org/wiki/Releases/4.18.0
https://security.gentoo.org/glsa/202210-22
https://access.redhat.com/security/cve/CVE-2021-35939
https://bugzilla.redhat.com/show_bug.cgi?id=1964129
https://github.com/rpm-software-management/rpm/commit/96ec957e281220f8e137a2d5eb23b83a6377d556
https://github.com/rpm-software-management/rpm/pull/1919
https://rpm.org/wiki/Releases/4.18.0
https://security.gentoo.org/glsa/202210-22

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