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CVE-2026-53220 Linux CVE debrief

CVE-2026-53220 is a vulnerability in the Linux kernel's netfilter component. The vulnerability arises from the ebt_redirect_tg() function, which dereferences the return value of br_port_get_rcu() without checking for NULL, leading to a kernel panic when the bridge port has been removed. The issue is exacerbated by the fact that userspace can not only remove the port from the bridge but also place the device in a different virtual device, such as macvlan. To address this, the fix switches to the _upper API, eliminating the need for the bridge port structure. This change also preserves another bug related to logging features when queueing in the bridge family. The CVE was published on 2026-06-25T09:16:39.743Z and last modified on 2026-06-30T14:44:27.313Z.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-25
Original CVE updated
2026-06-30
Advisory published
2026-06-25
Advisory updated
2026-06-30

Who should care

System administrators and security teams responsible for Linux kernel-based systems, particularly those using netfilter, should be aware of this vulnerability. The vulnerability's impact on system security and stability necessitates prompt attention and mitigation. Linux distributions and vendors should also take note of this issue to ensure their users are protected.

Technical summary

The vulnerability in the Linux kernel's netfilter component stems from the ebt_redirect_tg() function's lack of NULL checking on the return value of br_port_get_rcu(). This oversight leads to a kernel panic when the bridge port is removed between the original hook invocation and an NFQUEUE reinject. The fix involves switching to the _upper API to avoid reliance on the bridge port structure, addressing both the immediate vulnerability and an associated logging issue.

Defensive priority

High priority should be given to applying the necessary patches or mitigations to prevent exploitation of this vulnerability. System administrators should review their Linux kernel versions and update to a patched version as soon as possible.

Recommended defensive actions

  • Review and apply the relevant patches or updates to the Linux kernel.
  • Conduct a thorough inventory of systems using the affected Linux kernel versions.
  • Implement compensating controls, such as enhanced monitoring, to detect potential exploitation attempts.
  • Ensure that logging and queueing configurations are reviewed and adjusted according to the fix's implications.
  • Monitor for and respond to potential exploitation attempts or related security incidents.

Evidence notes

The CVE record and NVD detail provide official information on the vulnerability. Additional source references offer technical insights into the issue and its resolution. The Linux kernel's use of netfilter and the specific functions involved in the vulnerability are key to understanding the issue.

Official resources

This CVE debrief is AI-assisted and based on the supplied source corpus.