VulnerabilityPublished 25 Jun 2026Updated 21 Oct 2026

CVE-2026-53220: Linux kernel · netfilter: revalidate bridge ports

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in d4b1301fd3c9e5e105fd3767c68bc4ba558bb228 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in d4b1301fd3c9e5e105fd3767c68bc4ba558bb228, ccb9fd4b87538ccf19ccff78ee26700526d94867, 43330a1e8aace6b5a8de9aba127e9e394ab49b0f +2

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ f350a0a87374418635689471606454abc7beaa3a, < d4b1301fd3c9e5e105fd3767c68bc4ba558bb228	Fixed in d4b1301fd3c9e5e105fd3767c68bc4ba558bb228
LinuxLinux	Affected ≥ f350a0a87374418635689471606454abc7beaa3a, < ccb9fd4b87538ccf19ccff78ee26700526d94867	Fixed in ccb9fd4b87538ccf19ccff78ee26700526d94867
LinuxLinux	Affected ≥ f350a0a87374418635689471606454abc7beaa3a, < 43330a1e8aace6b5a8de9aba127e9e394ab49b0f	Fixed in 43330a1e8aace6b5a8de9aba127e9e394ab49b0f
LinuxLinux	Affected ≥ f350a0a87374418635689471606454abc7beaa3a, < 98cc0403f546c52104d654fa24d86e9bcac964d3	Fixed in 98cc0403f546c52104d654fa24d86e9bcac964d3
LinuxLinux	Affected ≥ f350a0a87374418635689471606454abc7beaa3a, < 4beffcd726e2a731cea4dc18e1fbc55c8d76f1a0	Fixed in 4beffcd726e2a731cea4dc18e1fbc55c8d76f1a0
LinuxLinux	Affected =2.6.36	Fixed in–

Description

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.

References

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