CVE-2021-33033: Use After Free
A flaw use-after-free in the Linux kernel CIPSO network packet labeling protocol functionality was found in the way user open local network connection with the usage of the security labeling that is IP option number 134. A local user could use this flaw to crash the system or possibly escalate their privileges on the system.
Other sources
Linux Kernel could allow a local attacker to execute arbitrary code on the system, caused by a use-after-free flaw in the cipsov4genopt function in net/ipv4/cipsoipv4.c. By sending a specially-crafted request, an attacker could exploit this vulnerability to execute arbitrary code or cause a denial of service condition on the system.
— IBM
The Linux kernel before 5.11.14 has a use-after-free in cipsov4genopt in net/ipv4/cipsoipv4.c because the CIPSO and CALIPSO refcounting for the DOI definitions is mishandled, aka CID-ad5d07f4a9cd. This leads to writing an arbitrary value.
The Linux kernel before 5.11.14 has a use-after-free in cipsov4genopt in net/ipv4/cipsoipv4.c because the CIPSO and CALIPSO refcounting for the DOI definitions is mishandled. This leads to writing an arbitrary value.
References: https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-cipsov4genopt https://syzkaller.appspot.com/bug?id=96e7d345748d8814901c91cd92084ed04b46701e
Upstream patches: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad5d07f4a9cd671233ae20983848874731102c08 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1165affd484889d4986cf3b724318935a0b120d8
— Red Hat
Affected Software
Remediation
Information
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2021-33033?
CVE-2021-33033 is classified as a critical vulnerability due to its potential to allow local users to crash the system or escalate privileges.
How do I fix CVE-2021-33033?
To remediate CVE-2021-33033, upgrade to the patched kernel versions specified by your Linux distribution.
Which Linux kernel versions are affected by CVE-2021-33033?
CVE-2021-33033 affects Linux kernel versions up to 5.11.14, including certain Red Hat and Debian versions.
Can CVE-2021-33033 be exploited remotely?
CVE-2021-33033 is considered a local vulnerability, meaning it requires local access to the system to exploit.
What implications does CVE-2021-33033 have for system security?
CVE-2021-33033 poses a significant security risk as it allows local users to potentially escalate privileges or crash the system.