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Linux KernelOperating system · Linux

CVE-2026-43208

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-06
Fix available
A fix is available. Upgrade to 6.18.16 / 6.19.6 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: net: do not pass flow_id to set_rps_cpu() Blamed commit made the assumption that the RPS table for each receive queue would have the same size, and that it would not change. Compute flow_id in set_rps_cpu(), do not assume we can use the value computed by get_rps_cpu(). Otherwise we risk out-of-bound access and/or crashes.

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 confidence

A vulnerability in the Linux kernel's RPS (Receive Packet Steering) mechanism allows out-of-bounds memory access. The bug occurs because set_rps_cpu() was reusing flow_id values computed by get_rps_cpu(), but the assumption that RPS tables for each receive queue have identical sizes that never change is incorrect. This can lead to out-of-bounds access and system crashes.

MitigationApply the kernel patch that computes flow_id directly in set_rps_cpu() rather than passing it from get_rps_cpu(), then deploy the updated kernel to affected systems. Given the critical CVSS 9.8 rating, prioritize patching.

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:>= 6.18, < 6.18.16>= 6.19, < 6.19.6= 7.0

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 the running kernel version
    Run 'uname -r' or 'cat /proc/version' to obtain the kernel version
    Affected if The version falls within >= 6.18 and < 6.18.16, OR >= 6.19 and < 6.19.6, OR equals 7.0
  2. Verify if RPS (Receive Packet Steering) is enabled
    Check for RPS configuration files in /proc/sys/net/core/rps_cpus or look at network device queue configuration via 'ethtool -g <device>'
    Affected if RPS is enabled for any network interface (non-zero rps_cpus value or multiple receive queues with RPS configured)
  3. Identify network devices with multiple receive queues
    Run 'ethtool -l <device>' or check /sys/class/net/<device>/queues/ directory for multiple rx-queues
    Affected if The system has network interfaces with multiple receive queues, which is required for RPS to be relevant
  4. Confirm RPS flow table configuration exists
    Examine /proc/sys/net/core/rps_flow_cnt or check the presence of RPS flow tables in /sys/class/net/<device>/queues/
    Affected if RPS flow tables are allocated, which would be impacted by the out-of-bounds access when flow_id values exceed table boundaries

The system is affected if it runs a vulnerable kernel version (6.18.x before 6.18.16, 6.19.x before 6.19.6, or 7.0) AND has RPS enabled on network interfaces with multiple receive queues, as the out-of-bounds memory access occurs when set_rps_cpu() reuses flow_id values from get_rps_cpu() against mismatched RPS table sizes.

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 6.18.16 / 6.19.6 or later
Fixed in 6.18.166.19.6
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch that computes flow_id directly in set_rps_cpu() rather than passing it from get_rps_cpu(), then deploy the updated kernel to affected systems. Given the critical CVSS 9.8 rating, prioritize patching.

Recommended fix High confidence

Upgrade to Linux Kernel 6.18.16 (or later 6.18.x), 6.19.6 (or later 6.19.x), or a version newer than 7.0

  1. Identify the currently running Linux kernel version using 'uname -r'
  2. Download or obtain the fixed kernel package for your distribution
  3. For RHEL/CentOS/Fedora: use 'dnf update kernel' or 'yum update kernel'
  4. For Debian/Ubuntu: use 'apt-get update && apt-get install linux-image-<version>'
  5. Ensure the system has sufficient disk space for the new kernel (typically 100-200MB extra)
  6. Reboot the system to boot into the fixed kernel version using 'sudo reboot'
  7. Select the fixed kernel from the GRUB menu during boot
  8. Verify the new kernel is running with 'uname -r' and confirm the version is >= 6.18.16, >= 6.19.6, or > 7.0
Caveat Kernel upgrades may require updating out-of-tree modules or drivers; ensure compatibility with your hardware before rebooting

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,080
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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-2026-43208 in production — separate from our analysis above.

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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
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  • No spam, self-promotion, credentials, or personal data