#VU57101 Out-of-bounds write in Linux kernel - CVE-2021-37576

Vulnerability identifier: #VU57101

Vulnerability risk: Medium

CVSSv4.0: 4.8 [CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-37576

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

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

Vendor: Linux Foundation

Description

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

The vulnerability exists due to a boundary error in arch/powerpc/kvm/book3s_rtas.c in the Linux kernel through 5.13.5 on the powerpc platform. An attacker on KVM guest OS can cause host OS memory corruption via rtas_args.nargs and execute arbitrary code on the host OS.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before 5.13.6, 5.13.6

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External links
https://lore.kernel.org/linuxppc-dev/87im0x1lqi.fsf@mpe.ellerman.id.au/T/#u
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f62f3c20647ebd5fb6ecb8f0b477b9281c44c10a
https://www.openwall.com/lists/oss-security/2021/07/27/2
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/Z2YZ2DNURMYYVDT2NYAFDESJC35KCUDS/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WDFA7DSQIPM7XPNXJBXFWXHJFVUBCAG6/
https://security.netapp.com/advisory/ntap-20210917-0005/
https://www.debian.org/security/2021/dsa-4978

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.