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Linux KernelOperating system · Linux

CVE-2026-46039

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-27
Fix available
A fix is available. Upgrade to 6.17 / 6.18.27 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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 · unedited
In the Linux kernel, the following vulnerability has been resolved: rxgk: Fix potential integer overflow in length check Fix potential integer overflow in rxgk_extract_token() when checking the length of the ticket. Rather than rounding up the value to be tested (which might overflow), round down the size of the available data.

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 confidence

Integer overflow vulnerability in rxgk_extract_token() in the Linux kernel's RxGK (Rx Gateway Key) implementation. The function incorrectly rounds up the length value during ticket validation checks, which can overflow and cause the length check to pass when it should fail. This allows potentially malicious or malformed tickets to bypass validation, leading to possible memory corruption or privilege escalation.

MitigationApply the kernel patch that modifies rxgk_extract_token() to round down the size of available data instead of rounding up the test value, preventing the integer overflow. Update to a kernel version containing this fix.

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
Affected:>= 6.16.9, < 6.17>= 6.17.1, < 6.18.27>= 6.19, < 7.0.4= 6.17

CVSS 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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check running kernel version
    Run 'uname -r' to obtain the currently running kernel version, then compare it against the affected ranges: >= 6.16.9, < 6.17; = 6.17; >= 6.17.1, < 6.18.27; >= 6.19, < 7.0.4
    Affected if The installed kernel version falls within any of the listed affected version ranges
  2. Verify rxgk module is loaded
    Run 'lsmod | grep rxgk' to check if the rxgk kernel module is currently loaded in memory
    Affected if The rxgk module is loaded and actively in use
  3. Check for rxgk module availability
    Run 'modinfo rxgk' or check for the presence of /lib/modules/$(uname -r)/kernel/net/rxgk.ko (or .xz) to determine if the rxgk module exists on the system
    Affected if The rxgk module is present on the system and could be loaded
  4. Inspect kernel config for rxgk support
    Check /boot/config-$(uname -r) or /proc/config.gz for CONFIG_RXGK=y or CONFIG_RXGK=m to see if rxgk support is compiled into the kernel or as a loadable module
    Affected if CONFIG_RXGK is set to y (built-in) or m (module) in the kernel configuration
  5. Identify services using rxgk protocol
    Review running services and configurations for any daemon or application that utilizes the rxgk protocol (such as OpenAFS if used over rxgk), as the vulnerability is triggerable when processing rxgk tickets
    Affected if Any network service or application using the rxgk protocol is running and accessible

A system is affected if it runs a Linux kernel version within the specified ranges AND has the rxgk module compiled, available, or loaded, and processes rxgk protocol traffic.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 6.17 / 6.18.27 / 7.0.4 or later
Fixed in 6.176.18.277.0.4
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch that modifies rxgk_extract_token() to round down the size of available data instead of rounding up the test value, preventing the integer overflow. Update to a kernel version containing this fix.

Recommended fix High confidence

Upgrade to kernel version 6.18.27, 7.0.4, or later stable release (e.g., 6.18.x or 7.0.x series)

  1. Identify your current kernel version using 'uname -r'
  2. Check if your version is in the affected range: >= 6.16.9 and < 6.17, = 6.17, >= 6.17.1 and < 6.18.27, >= 6.19 and < 7.0.4
  3. If affected, update your distribution's kernel package to a fixed version (see upgrade_path)
  4. Reboot the system to load the new kernel
  5. Verify the new kernel version is loaded using 'uname -r'
Caveat Kernel upgrades may require system reboot and could have compatibility implications with custom modules or specific hardware drivers; test in staging environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA3.0 h
14.0 hours of engineering $2,400
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-46039 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data