Important: kernel

Issue Overview:

2024-02-01: CVE-2023-0590 was added to this advisory.

2024-01-19: CVE-2023-52340 was added to this advisory.

A use-after-free flaw was found in qdisc_graft in net/sched/sch_api.c in the Linux Kernel due to a race problem. This flaw leads to a denial of service issue. (CVE-2023-0590)

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.

Patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=af6d10345ca76670c1b7c37799f0d5576ccef277 (CVE-2023-52340)

A use-after-free vulnerability in the Linux kernel’s ipv4: igmp component can be exploited to achieve local privilege escalation.

A race condition can be exploited to cause a timer be mistakenly registered on a RCU read locked object which is freed by another thread.

We recommend upgrading past commit e2b706c691905fe78468c361aaabc719d0a496f1. (CVE-2023-6932)

Affected Packages:

kernel

Issue Correction:
Run yum update kernel to update your system.

New Packages:

i686:  
    perf-debuginfo-4.14.334-177.552.amzn1.i686  
    kernel-tools-devel-4.14.334-177.552.amzn1.i686  
    kernel-tools-debuginfo-4.14.334-177.552.amzn1.i686  
    kernel-headers-4.14.334-177.552.amzn1.i686  
    kernel-4.14.334-177.552.amzn1.i686  
    kernel-devel-4.14.334-177.552.amzn1.i686  
    kernel-debuginfo-4.14.334-177.552.amzn1.i686  
    kernel-tools-4.14.334-177.552.amzn1.i686  
    perf-4.14.334-177.552.amzn1.i686  
    kernel-debuginfo-common-i686-4.14.334-177.552.amzn1.i686  
  
src:  
    kernel-4.14.334-177.552.amzn1.src  
  
x86_64:  
    perf-4.14.334-177.552.amzn1.x86_64  
    kernel-tools-debuginfo-4.14.334-177.552.amzn1.x86_64  
    kernel-tools-4.14.334-177.552.amzn1.x86_64  
    kernel-tools-devel-4.14.334-177.552.amzn1.x86_64  
    kernel-debuginfo-common-x86_64-4.14.334-177.552.amzn1.x86_64  
    kernel-headers-4.14.334-177.552.amzn1.x86_64  
    perf-debuginfo-4.14.334-177.552.amzn1.x86_64  
    kernel-4.14.334-177.552.amzn1.x86_64  
    kernel-devel-4.14.334-177.552.amzn1.x86_64  
    kernel-debuginfo-4.14.334-177.552.amzn1.x86_64  

Additional References

Red Hat: CVE-2023-0590, CVE-2023-52340, CVE-2023-6932

Mitre: CVE-2023-0590, CVE-2023-52340, CVE-2023-6932