NULL Pointer Dereference Affecting perf6.18-debuginfo package, versions <1:6.18.36-69.134.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.12% (3rd percentile)

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  • Snyk IDSNYK-AMZN2023-PERF618DEBUGINFO-18062085
  • published21 Jul 2026
  • disclosed25 Jun 2026

Introduced: 25 Jun 2026

CVE-2026-53220  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 perf6.18-debuginfo to version 1:6.18.36-69.134.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1925.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf6.18-debuginfo package and not the perf6.18-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:

netfilter: revalidate bridge ports

ebt_redirect_tg() dereferences br_port_get_rcu() return without a NULL check, causing a kernel panic when the bridge port has been removed between the original hook invocation and an NFQUEUE reinject.

A mere NULL check isn't sufficient, however. As sashiko review points out userspace can not only remove the port from the bridge, it could also place the device in a different virtual device, e.g. macvlan.

If this happens, we must drop the packet, there is no way for us to reinject it into the bridge path.

Switch to _upper API, we don't need the bridge port structure. Also, this fix keeps another bug intact:

Both nfnetlink_log and nfnetlink_queue use CONFIG_BRIDGE_NETFILTER too aggressive, which prevents certain logging features when queueing in bridge family: NETFILTER_FAMILY_BRIDGE can be enabled while the old CONFIG_BRIDGE_NETFILTER cruft is off.

Fixes tag is a common ancestor, this was always broken.

CVSS Base Scores

version 3.1