Vulnerability identifier: #VU55143

Vulnerability risk: Low

CVSSv3.1:

CVE-ID: CVE-2021-33909

CWE-ID:

Exploitation vector: Local

Exploit availability:

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

Vendor:

Description

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

The vulnerability exists due to integer overflow during size_t-to-int conversion when creating, mounting, and deleting a deep directory structure whose total path length exceeds 1GB. An unprivileged local user can write up to 10-byte string to an offset of exactly -2GB-10B below the beginning of a vmalloc()ated kernel buffer.

Successful exploitation of vulnerability may allow an attacker to exploit the our-of-bounds write vulnerability to execute arbitrary code with root privileges.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

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External links
http://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.4
http://github.com/torvalds/linux/commit/8cae8cd89f05f6de223d63e6d15e31c8ba9cf53b
http://www.openwall.com/lists/oss-security/2021/07/20/1

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Q & A

Can this vulnerability be exploited remotely?

Is there known malware, which exploits this vulnerability?