CVE-2023-52340: High severity Linux Linux kernel vulnerability
A flaw in the Linux Kernel found. When a router encounters an IPv6 packet too big to transmit to the next-hop, it returns an ICMP6 "Packet Too Big" (PTB) message to the sender. The sender caches this updated Maximum Transmission Unit (MTU) so it knows not to exceed this value when subsequently routing to the same host. In Linux kernels prior to 6.3, garbage collection is run on the IPv6 Destination Route Cache if the number of entries exceeds a threshold when adding the destination to the cache. This garbage collection examines every entry in the cache while holding a lock. In these affected kernel versions, a flood of the IPv6 ICMP6 PTB messages could cause high lock contention and increased CPU usage, leading to a Denial-of-Service.
The fix backports the garbage collection improvements from Linux kernel 6.3 by bringing the IPv6 code closer to the IPv4 code, which does not have this issue.
References: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=af6d10345ca76670c1b7c37799f0d5576ccef277 https://alas.aws.amazon.com/cve/html/CVE-2023-52340.html
Other sources
The IPv6 implementation in the Linux kernel before 6.3 has a net/ipv6/route.c maxsize threshold that can be consumed easily, e.g., leading to a denial of service (network is unreachable errors) when IPv6 packets are sent in a loop via a raw socket.
— MITRE
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2023-52340?
CVE-2023-52340 is classified as a medium severity vulnerability in the Linux Kernel.
How do I fix CVE-2023-52340?
To fix CVE-2023-52340, update your Linux Kernel to version 6.3 or later.
Which versions of the Linux Kernel are affected by CVE-2023-52340?
CVE-2023-52340 affects all versions of the Linux Kernel up to 6.3.
Is CVE-2023-52340 specific to any Linux distributions?
CVE-2023-52340 impacts various Linux distributions including Red Hat and Debian.
Are there any known exploits for CVE-2023-52340?
As of now, there are no known public exploits for CVE-2023-52340.