Linux KernelOperating system · Linux
CVE-2026-53000
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: nat: use kfree_rcu to release ops Florian Westphal says: "Historically this is not an issue, even for normal base hooks: the data path doesn't use the original nf_hook_ops that are used to register the callbacks. However, in v5.14 I added the ability to dump the active netfilter hooks from userspace. This code will peek back into the nf_hook_ops that are available at the tail of the pointer-array blob used by the datapath. The nat hooks are special, because they are called indirectly from the central nat dispatcher hook. They are currently invisible to the nfnl hook dump subsystem though. But once that changes the nat ops structures have to be deferred too." Update nf_nat_register_fn() to deal with partial exposition of the hooks from error path which can be also an issue for nfnetlink_hook.
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 · high confidenceThe Linux kernel netfilter NAT subsystem incorrectly frees nf_hook_ops structures using regular kfree instead of kfree_rcu. Since Linux 5.14, userspace can dump active netfilter hooks, which accesses these ops structures. If freed immediately while being accessed during a dump, this creates a use-after-free condition leading to potential privilege escalation or information disclosure.
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
>= 5.14, < 6.18.33>= 6.19, < 7.0.10
Enterprise LinuxOperating system
= 9.0= 10.0CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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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Identify running kernel versionRun 'uname -r' to obtain the exact kernel version stringAffected if The version is >= 5.14 and < 6.18.33, or >= 6.19 and < 7.0.10 (including 6.18.33 and 7.0.10 themselves which contain the fix)
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Check netfilter NAT module loadedRun 'lsmod | grep nf_nat' to see if the NAT module is currently loaded in memoryAffected if The nf_nat or nf_nat_.* modules appear in the loaded module list
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Detect active NAT rulesRun 'iptables -t nat -L -n 2>/dev/null' or 'nft list table ip nat 2>/dev/null' to list any configured NAT rulesAffected if Any NAT table rules (PREROUTING, POSTROUTING, OUTPUT chains) are present and active
The system is affected if the kernel version is within the vulnerable ranges AND netfilter NAT functionality is loaded or configured, since the race condition triggers during hook dump operations on active NAT hooks.
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 · scoped6.18.337.0.10
Update nf_nat_register_fn() to use kfree_rcu for deferred release of nat ops structures, ensuring hooks are not freed while being accessed by the nfnl hook dump subsystem.
Linux Kernel 6.18.33 or later, or 7.0.10 or later | RHEL 9.0 Update (kernel-5.14.0-xxx or later with fix) | RHEL 10.0 Update (kernel-6.14.0-xxx or later with fix)
- Check current kernel version: `uname -r`
- For RHEL/CentOS Stream and RHEL 9/10: Run `dnf update kernel` to install the latest kernel package containing the fix
- Reboot the system to load the fixed kernel: `systemctl reboot`
- Verify the new kernel version is loaded: `uname -r`
- Confirm the fix is present by checking the netfilter NAT code includes kfree_rcu for ops release (if debugging symbol packages are installed)
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
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-53000 — 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-2026-53000 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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