#VU60357 Use-after-free in Linux kernel - CVE-2021-29266

Vulnerability identifier: #VU60357

Vulnerability risk: Low

CVSSv4.0: 4.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-29266

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

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

The vulnerability exists due to a use-after-free error in drivers/vhost/vdpa.c, because "v->config_ctx" has an invalid value upon re-opening a character device. A local user can trigger a use-after-free error and execute arbitrary code with elevated privileges.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: 5.11.1 - 5.11.8

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External links
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.9
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f6bbf0010ba004f5e90c7aefdebc0ee4bd3283b9
https://security.netapp.com/advisory/ntap-20210513-0005/

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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.