#VU55975 Out-of-bounds write in Linux kernel - CVE-2021-3490
Published: August 19, 2021 / Updated: February 14, 2024
Vulnerability identifier: #VU55975
Vulnerability risk: Low
CVSSv4.0: 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:A/U:Clear
CVE-ID: CVE-2021-3490
CWE-ID: CWE-787
Exploitation vector: Local access
Exploit availability:
The vulnerability is being exploited in the wild
Vulnerable software:
Linux kernel
Linux kernel
Software vendor:
Linux Foundation
Linux Foundation
Description
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error when processing untrusted input in bpf. The eBPF ALU32 bounds tracking for bitwise ops (AND, OR and XOR) in the
Linux kernel did not properly update 32-bit bounds, which could be
turned into out of bounds reads and writes in the Linux kernel and
therefore, arbitrary code execution. A local user can run a specially crafted program to trigger an out-of-bounds write and execute arbitrary code with elevated privileges.
Remediation
Install updates from vendor's website.
External links
- https://ubuntu.com/security/notices/USN-4949-1
- https://www.zerodayinitiative.com/advisories/ZDI-21-606/
- https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=049c4e13714ecbca567b4d5f6d563f05d431c80e
- https://ubuntu.com/security/notices/USN-4950-1
- https://www.openwall.com/lists/oss-security/2021/05/11/11
- https://security.netapp.com/advisory/ntap-20210716-0004/