#VU79521 Link following in rpm - CVE-2021-35938

Vulnerability identifier: #VU79521

Vulnerability risk: Low

CVSSv4.0: 5.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-35938

CWE-ID: CWE-59

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
rpm

Vendor: rpm-software-management

Description

The vulnerability allows a local privileged user to escalate privileges on the system.

The vulnerability occurs when rpm sets the desired permissions and credentials after installing a file. A local privileged user can use this flaw to exchange the original file with a symbolic link to a security-critical file and escalate their privileges on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

rpm: before 4.18.0

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External links
https://bugzilla.redhat.com/show_bug.cgi?id=1964114
https://github.com/rpm-software-management/rpm/pull/1919
https://bugzilla.suse.com/show_bug.cgi?id=1157880
https://github.com/rpm-software-management/rpm/commit/25a435e90844ea98fe5eb7bef22c1aecf3a9c033
https://access.redhat.com/security/cve/CVE-2021-35938
https://rpm.org/wiki/Releases/4.18.0
https://security.gentoo.org/glsa/202210-22

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.