#VU47074 Race condition in Linux kernel - CVE-2020-10766

Vulnerability identifier: #VU47074

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-2020-10766

CWE-ID: CWE-362

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 gain access to sensitive information.

A logic bug flaw was found in Linux kernel before 5.8-rc1 in the implementation of SSBD. A bug in the logic handling allows an attacker with a local account to disable SSBD protection during a context switch when additional speculative execution mitigations are in place. This issue was introduced when the per task/process conditional STIPB switching was added on top of the existing SSBD switching.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 5.0 - 5.0.21, 5.1 rc1 - 5.1.21, 5.2 - 5.2.21, 5.3 - 5.3.18, 5.4 - 5.4.42, 5.5 - 5.5.19, 5.6 - 5.6.14, 5.7 - 5.7.7

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External links
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-10766
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dbbe2ad02e9df26e372f38cc3e70dab9222c832e

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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.