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Amazon Linux AMI: CVE-2023-4623: Security patch for kernel (ALAS-2023-1838)

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Amazon Linux AMI: CVE-2023-4623: Security patch for kernel (ALAS-2023-1838)

Severity
4
CVSS
(AV:L/AC:M/Au:N/C:P/I:P/A:P)
Published
09/06/2023
Created
10/11/2023
Added
10/07/2023
Modified
10/07/2023

Description

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.

Solution(s)

  • amazon-linux-upgrade-kernel

References

  • ALAS-2023-1838
  • CVE-2023-4623

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