CVE-2023-4244: Use-after-free in Linux kernel's netfilter: nf_tables component
A use-after-free flaw was found in nftables sub-component due to a race problem between set GC and transaction in the Linux Kernel. This flaw could allow a local attacker to crash the system, due to missing call to to nftsetelemmarkbusy causing double deactivation of the element. This vulnerability could even lead to a kernel information leak problem.
Refer: https://lore.kernel.org/netdev/20230810070830.24064-1-pablo@netfilter.org/ https://lore.kernel.org/netdev/20230815223011.7019-1-fw@strlen.de/
Other sources
A use-after-free vulnerability in the Linux kernel's netfilter: nftables component can be exploited to achieve local privilege escalation.
Due to a race condition between nftables netlink control plane transaction and nftset element garbage collection, it is possible to underflow the reference counter causing a use-after-free vulnerability.
We recommend upgrading past commit 3e91b0ebd994635df2346353322ac51ce84ce6d8.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/Kernelto a version that resolves this vulnerability.Fixed in 6.5 - 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 6.12.27-1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch 3e91b0ebd994635df2346353322ac51ce84ce6d8 - Configuration
Disable unprivileged user namespace creation (temporary: `sysctl -w kernel.unprivileged_userns_clone=0`; across reboots: write `/etc/sysctl.d/99-disable-unpriv-userns.conf` via `tee` and set `kernel.unprivileged_userns_clone=0`).
Linux kernel kernel.unprivileged_userns_clone = 0
Event History
Frequently Asked Questions
What is CVE-2023-4244?
CVE-2023-4244 is a use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component.
How can CVE-2023-4244 be exploited?
CVE-2023-4244 can be exploited to achieve local privilege escalation.
What is the severity of CVE-2023-4244?
CVE-2023-4244 has a severity rating of 7.8 (high).
What software is affected by CVE-2023-4244?
CVE-2023-4244 affects the Linux kernel version 6.5 and below.
Is there a fix for CVE-2023-4244?
Yes, a fix for CVE-2023-4244 is available. Please refer to the provided references for more information on the fix.