SB2021072271 - Privilege escalation in Linux kernel
Published: July 22, 2021
Security Bulletin ID
SB2021072271
Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Use-after-free (CVE-ID: CVE-2021-33033)
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 update from vendor's website.
References
- 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