Expired Pointer Dereference Affecting kernel6.18-debuginfo package, versions <1:6.18.54-121.166.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.14% (3rd percentile)

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  • Snyk IDSNYK-AMZN2023-KERNEL618DEBUGINFO-21424880
  • published22 Oct 2026
  • disclosed6 Oct 2026

Introduced: 6 Oct 2026

NewCVE-2026-98253  (opens in a new tab)
CWE-825  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel6.18-debuginfo to version 1:6.18.54-121.166.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3192.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel6.18-debuginfo package and not the kernel6.18-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

RDMA/ucma: Serialize join and leave on copy_to_user failure

rdma_join_multicast() queues RoCE work that later reads the ucma_multicast through event->param.ud.private_data, then list_add()s the CMA multicast at the head of id_priv->mc_list. rdma_leave_multicast() matches only by sockaddr and destroys the first hit.

ucma_process_join() used to drop ctx->mutex after a successful join and retake it only if copy_to_user() failed. Two concurrent JOIN_MCAST calls with the same address can therefore insert a second CMA entry before the first thread's leave. leave then cancels the newer work and the older worker still dereferences the ucma_multicast that the first thread frees.

Keep ctx->mutex held from rdma_join_multicast() through copy_to_user() and, on -EFAULT, through rdma_leave_multicast() so leave cannot miss this join. Do not leave if join itself failed: that path never published this address on mc_list, and a leave-by-addr would destroy an earlier successful join.

CVSS Base Scores

version 3.1