Linux KernelOperating system · Linux
CVE-2026-53001
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn the Linux kernel, the following vulnerability has been resolved: netfilter: xtables: restrict several matches to inet family This is a partial revert of: commit ab4f21e6fb1c ("netfilter: xtables: use NFPROTO_UNSPEC in more extensions") to allow ipv4 and ipv6 only. - xt_mac - xt_owner - xt_physdev These extensions are not used by ebtables in userspace. Moreover, xt_realm is only for ipv4, since dst->tclassid is ipv4 specific.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThe Linux kernel netfilter/xtables subsystem incorrectly allowed several match extensions (xt_mac, xt_owner, xt_physdev, xt_realm) to operate with NFPROTO_UNSPEC (both IPv4 and IPv6 families). The xt_realm match uses dst->tclassid which is IPv4-specific, and the other extensions are not used by ebtables in userspace. This misconfiguration could lead to incorrect behavior or crashes when these matches are applied to the wrong IP family.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
>= 2.6.28, < 5.10.258>= 5.11, < 5.15.209>= 5.16, < 6.1.175>= 6.2, < 6.6.141>= 6.7, < 6.12.91>= 6.13, < 6.18.33>= 6.19, < 7.0.10CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check the kernel versionRun 'uname -r' or 'cat /proc/version' to obtain the running kernel versionAffected if The kernel version falls within any of the affected ranges: >= 2.6.28 and < 5.10.258; >= 5.11 and < 5.15.209; >= 5.16 and < 6.1.175; >= 6.2 and < 6.6.141; >= 6.7 and < 6.12.91; >= 6.13 and < 6.18.33; >= 6.19 and < 7.0.10
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Verify netfilter module availabilityCheck if the affected modules exist: ls /lib/modules/$(uname -r)/kernel/net/netfilter/ | grep -E 'xt_mac|xt_owner|xt_physdev|xt_realm'Affected if Any of these modules (xt_mac, xt_owner, xt_physdev, xt_realm) are present on the system and the kernel version is in the affected range
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List active iptables rules using the vulnerable matchesRun 'iptables -L -n -v' and 'ip6tables -L -n -v' to list all rules, then search for rules using --mac-source (xt_mac), --uid-owner/--gid-owner (xt_owner), --physdev-in/--physdev-out (xt_physdev), or --realm (xt_realm)Affected if Any rules using these matches exist in either iptables (IPv4) or ip6tables (IPv6) tables, especially in the filter or raw tables
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Identify rules without inet family restrictionRun 'iptables -L -n -v --line-numbers' and 'ip6tables -L -n -v --line-numbers' for each table (filter, nat, mangle, raw) and examine if rules specify '-p ipv4-icmp' or '-p ipv6-icmp' or use the '-m' extension without explicit protocol familyAffected if Rules using xt_realm are found in ip6tables (IPv6) context, or rules using xt_mac/xt_owner/xt_physdev are found in contexts that could use NFPROTO_UNSPEC (neither IPv4 nor IPv6 protocol is explicitly specified)
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Check for kernel crash logs related to netfilterReview dmesg output and /var/log/kern.log for messages containing 'netfilter', 'xt_', 'panic', 'BUG', or 'unable to handle' occurring after loading these rulesAffected if Kernel panics, oops messages, or crashes occur when these match extensions are used, particularly with non-IPv4 traffic
A system is affected if it runs a kernel version within the affected ranges AND has active iptables/ip6tables rules using xt_mac, xt_owner, xt_physdev, or xt_realm matches, especially when those rules lack explicit IPv4 or IPv6 protocol family specification.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped5.10.2585.15.2096.1.175
Apply the kernel security update containing this fix, which restricts these match extensions to inet family (IPv4/IPv6) as appropriate. For xt_realm specifically, restrict to IPv4 only.
Upgrade to kernel 5.10.258+, 5.15.209+, 6.1.175+, 6.6.141+, or latest stable (6.7+) depending on your current branch
- 1. Identify the currently running Linux kernel version using `uname -r`
- 2. Determine which version range your current kernel falls into from the affected versions list
- 3. For kernels >= 2.6.28 and < 5.10.258: upgrade to kernel version 5.10.258 or later
- 4. For kernels >= 5.11 and < 5.15.209: upgrade to kernel version 5.15.209 or later
- 5. For kernels >= 5.16 and < 6.1.175: upgrade to kernel version 6.1.175 or later
- 6. For kernels >= 6.2 and < 6.6.141: upgrade to kernel version 6.6.141 or later
- 7. For kernels >= 6.7: upgrade to the latest stable kernel release (6.7.x or newer) which should contain the fix
- 8. After upgrading, verify the kernel version with `uname -r` and reboot into the new kernel
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,936.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-53001 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-53001 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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