#VU55261 Use-after-free in Linux kernel - CVE-2021-33033
Published: July 22, 2021
Vulnerability identifier: #VU55261
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:U/U:Clear
CVE-ID: CVE-2021-33033
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
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 improper handling of the CIPSO and CALIPSO refcounting for the DOI definitions in cipso_v4_genopt(0 function in net/ipv4/cipso_ipv4.c in Linux kernel. A local user can trigger a use-after-free error and execute arbitrary code with escalated privileges.
Remediation
Install updates from vendor's website.
External links
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad5d07f4a9cd671233ae20983848874731102c08
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.14
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.7
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1165affd484889d4986cf3b724318935a0b120d8
- https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-cipso_v4_genopt
- https://syzkaller.appspot.com/bug?id=96e7d345748d8814901c91cd92084ed04b46701e