#VU56018 Buffer overflow in Linux kernel - CVE-2021-22543
Vulnerability identifier: #VU56018
Vulnerability risk: Low
CVSSv4.0: 7.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]
CVE-ID:
CWE-ID:
CWE-119
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 escalate privileges on the system.
The vulnerability exists due to a boundary error in Linux kernel when handling VM_IO|VM_PFNMAP vmas in KVM. A local user can can bypass RO checks and cause the pages to get freed while still accessible by the VMM and guest. As a result, an attacker with the ability to start and control a VM to read/write random pages of memory, can trigger memory corruption and execute arbitrary code with elevated privileges.
Mitigation
Install updates from vendor's website.
Vulnerable software versions
Linux kernel: All versions
External links
https://github.com/google/security-research/security/advisories/GHSA-7wq5-phmq-m584
https://www.openwall.com/lists/oss-security/2021/06/26/1
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ROQIXQB7ZAWI3KSGSHR6H5RDUWZI775S/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4G5YBUVEPHZYXMKNGBZ3S6INFCTEEL4E/
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.
