#VU51550 Security restrictons bypass in Linux kernel - CVE-2020-29373

Vulnerability identifier: #VU51550

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-29373

CWE-ID: CWE-264

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 in fs/io_uring.c in the Linux kernel due to insecure handling of the root directory during path lookups. A process inside a mount namespace can escape to unintended filesystem locations and read sensitive information.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.6, 5.6

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External links
https://bugs.chromium.org/p/project-zero/issues/detail?id=2011
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.6
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ff002b30181d30cdfbca316dadd099c3ca0d739c

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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.