CVE-2021-4203: Race Condition
A use-after-free read flaw was found in sockgetsockopt() in net/core/sock.c due to SOPEERCRED and SOPEERGROUPS race with listen() (and connect()) in the Linux kernel. In this flaw, an attacker with a user privilege may lead to a system crash or a leak of internal kernel information.
In this, if the creds are replaced and freed at the wrong time, a use-after-free read occurs.
References:
https://lore.kernel.org/netdev/20210929225750.2548112-1-eric.dumazet@gmail.com/T/ https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=35306eb23814 https://bugs.chromium.org/p/project-zero/issues/detail?id=2230&can=7&q=modified-after%3Atoday-30&sort=-modified&colspec=ID%20Type%20Status%20Priority%20Milestone%20Owner%20Summary%20Modified%20Cve&cells=tiles&redir=1
Other sources
A use-after-free read flaw was found in sockgetsockopt() in net/core/sock.c due to SOPEERCRED and SOPEERGROUPS race with listen() (and connect()) in the Linux kernel. In this flaw, an attacker with a user privileges may crash the system or leak internal kernel information.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:4.18.0-372.9.1.rt7.166.el8 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:4.18.0-372.9.1.el8 - Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:4.18.0-305.57.1.rt7.129.el8_4 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:4.18.0-305.57.1.el8_4 - Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.223-1Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 5.15
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2021-4203?
CVE-2021-4203 is rated as having a high severity level due to its potential to cause system crashes or leak internal kernel information.
How do I fix CVE-2021-4203?
To remediate CVE-2021-4203, upgrade to the recommended kernel versions as specified in security advisories or vendor documentation.
What type of vulnerability is CVE-2021-4203?
CVE-2021-4203 is a use-after-free read flaw in the Linux kernel that can be exploited due to improper handling of socket options.
Who is affected by CVE-2021-4203?
Users of vulnerable versions of the Linux kernel, specifically those using certain Red Hat and Debian kernels, are at risk from CVE-2021-4203.
What conditions are necessary for CVE-2021-4203 to be exploited?
An attacker must have user privileges on the system to exploit CVE-2021-4203, allowing them to trigger the vulnerability.