#VU62662 Use-after-free in selinux - CVE-2021-36086

Vulnerability identifier: #VU62662

Vulnerability risk: Low

CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-36086

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
selinux
Other software / Other software solutions

Vendor: SELinux Project

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to a use-after-free error within the cil_reset_classpermission() function in CIL compiler in SELinux. A local user can perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

selinux: before 3.3

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External links
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=32177
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/selinux/OSV-2021-536.yaml
https://github.com/SELinuxProject/selinux/commit/c49a8ea09501ad66e799ea41b8154b6770fec2c8
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U7ZYR3PIJ75N6U2IONJWCKZ5L2NKJTGR/

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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.