Important: kernel

Issue Overview:

A flaw was found in the Linux kernel’s IP framework for transforming packets (XFRM subsystem). This issue may allow a malicious user with CAP_NET_ADMIN privileges to directly dereference a NULL pointer in xfrm_update_ae_params(), leading to a possible kernel crash and denial of service. (CVE-2023-3772)

A use-after-free vulnerability in the Linux kernel’s net/sched: cls_fw component can be exploited to achieve local privilege escalation.

When fw_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.

We recommend upgrading past commit 76e42ae831991c828cffa8c37736ebfb831ad5ec. (CVE-2023-4207)

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

The unix_stream_sendpage() function tries to add data to the last skb in the peer’s recv queue without locking the queue. Thus there is a race where unix_stream_sendpage() could access an skb locklessly that is being released by garbage collection, resulting in use-after-free.

We recommend upgrading past commit 790c2f9d15b594350ae9bca7b236f2b1859de02c. (CVE-2023-4622)

A use-after-free vulnerability in the Linux kernel’s net/sched: sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation.

If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free.

We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f. (CVE-2023-4623)

A use-after-free vulnerability in the Linux kernel’s net/sched: sch_qfq component can be exploited to achieve local privilege escalation.

When the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug and lack of error checking in agg_dequeue().

We recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8. (CVE-2023-4921)

Affected Packages:

kernel

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

New Packages:

aarch64:  
    kernel-4.14.326-245.539.amzn2.aarch64  
    kernel-headers-4.14.326-245.539.amzn2.aarch64  
    kernel-debuginfo-common-aarch64-4.14.326-245.539.amzn2.aarch64  
    perf-4.14.326-245.539.amzn2.aarch64  
    perf-debuginfo-4.14.326-245.539.amzn2.aarch64  
    python-perf-4.14.326-245.539.amzn2.aarch64  
    python-perf-debuginfo-4.14.326-245.539.amzn2.aarch64  
    kernel-tools-4.14.326-245.539.amzn2.aarch64  
    kernel-tools-devel-4.14.326-245.539.amzn2.aarch64  
    kernel-tools-debuginfo-4.14.326-245.539.amzn2.aarch64  
    kernel-devel-4.14.326-245.539.amzn2.aarch64  
    kernel-debuginfo-4.14.326-245.539.amzn2.aarch64  
  
i686:  
    kernel-headers-4.14.326-245.539.amzn2.i686  
  
src:  
    kernel-4.14.326-245.539.amzn2.src  
  
x86_64:  
    kernel-4.14.326-245.539.amzn2.x86_64  
    kernel-headers-4.14.326-245.539.amzn2.x86_64  
    kernel-debuginfo-common-x86_64-4.14.326-245.539.amzn2.x86_64  
    perf-4.14.326-245.539.amzn2.x86_64  
    perf-debuginfo-4.14.326-245.539.amzn2.x86_64  
    python-perf-4.14.326-245.539.amzn2.x86_64  
    python-perf-debuginfo-4.14.326-245.539.amzn2.x86_64  
    kernel-tools-4.14.326-245.539.amzn2.x86_64  
    kernel-tools-devel-4.14.326-245.539.amzn2.x86_64  
    kernel-tools-debuginfo-4.14.326-245.539.amzn2.x86_64  
    kernel-devel-4.14.326-245.539.amzn2.x86_64  
    kernel-debuginfo-4.14.326-245.539.amzn2.x86_64  
    kernel-livepatch-4.14.326-245.539-1.0-0.amzn2.x86_64  

Additional References

Red Hat: CVE-2023-3772, CVE-2023-4207, CVE-2023-4622, CVE-2023-4623, CVE-2023-4921

Mitre: CVE-2023-3772, CVE-2023-4207, CVE-2023-4622, CVE-2023-4623, CVE-2023-4921