#VU67490 Out-of-bounds read in Linux kernel - CVE-2021-29155

Vulnerability identifier: #VU67490

Vulnerability risk: Low

CVSSv4.0: 5.2 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2021-29155

CWE-ID: CWE-125

Exploitation vector: Local

Exploit availability: Yes

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

Vendor: Linux Foundation

Description

The vulnerability allows a local user to gain access to potentially sensitive information.

The vulnerability exists in retrieve_ptr_limit in kernel/bpf/verifier.c in the Linux kernel mechanism. A local, special user privileged (CAP_SYS_ADMIN) BPF program running on affected systems may bypass the protection, and execute speculatively out-of-bounds loads from the kernel memory.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.12, 5.12

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External links
https://www.kernel.org
https://www.openwall.com/lists/oss-security/2021/04/18/4

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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. However, proof of concept for this vulnerability is available.