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Linux KernelOperating system · Linux

CVE-2023-2156

HIGH · 7.5 CVSS v3.1 Published 2023-05-09
Fix available
A fix is available. Upgrade to 5.10.184 / 5.15.117 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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
A flaw was found in the networking subsystem of the Linux kernel within the handling of the RPL protocol. This issue results from the lack of proper handling of user-supplied data, which can lead to an assertion failure. This may allow an unauthenticated remote attacker to create a denial of service condition on the system.

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 exists in the Linux kernel's networking subsystem in the RPL (Routing Protocol for Low-Power and Lossy Networks) protocol handling. The flaw stems from improper validation of user-supplied data, which can trigger an assertion failure and cause a denial of service. An unauthenticated remote attacker can exploit this without authentication.

MitigationApply the Linux kernel patch for CVE-2023-2156, which involves updating to a patched kernel version. Given this is a denial-of-service vulnerability in the networking stack, prioritize patching systems exposed to untrusted RPL traffic, particularly those in IoT or constrained network environments.

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:>= 5.7, < 5.10.184>= 5.11, < 5.15.117>= 5.16, < 6.1.34>= 6.2, < 6.2.13>= 6.3, < 6.3.8
Enterprise LinuxOperating system
Affected:= 9.0
FedoraOperating system
Affected:= 38
Debian LinuxOperating system
Affected:= 10.0

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
None
Integrity
None
Availability
High

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

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

  1. Check kernel version
    Run `uname -r` or `cat /proc/version` to get the installed kernel version
    Affected if The version falls within any of these ranges: >= 5.7 and < 5.10.184; >= 5.11 and < 5.15.117; >= 5.16 and < 6.1.34; >= 6.2 and < 6.2.13; >= 6.3 and < 6.3.8
  2. Verify RPL kernel module is loaded
    Run `lsmod | grep -i rpl` to see if the RPL module is currently loaded into the kernel
    Affected if The rpl module appears in the output, indicating RPL protocol support is active
  3. Check RPL sysctl configuration
    Run `sysctl -a 2>/dev/null | grep -i rpl` to inspect RPL-related kernel parameters
    Affected if Any RPL-related sysctl parameters exist and are configured (non-zero or non-default values), indicating RPL is enabled
  4. Check for RPL interface configuration
    Run `ip -6 route show` and look for rpl entries, or check `cat /proc/net/ipv6_route` for rpl-related routes
    Affected if RPL-specific routes or interfaces appear in the IPv6 routing table, confirming active RPL protocol usage
  5. Check distro-specific kernel package version
    For RHEL: `rpm -q kernel`; Fedora: `rpm -q kernel-core`; Debian: `dpkg -l | grep linux-image`
    Affected if The installed kernel package version matches the affected distro versions (RHEL 9.0, Fedora 38, Debian 10.0)

The system is affected if it runs a vulnerable kernel version AND has RPL protocol module loaded or enabled in the network configuration.

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 5.10.184 / 5.15.117 / 6.1.34 or later
Fixed in 5.10.1845.15.1176.1.34
Interim mitigation

Apply the Linux kernel patch for CVE-2023-2156, which involves updating to a patched kernel version. Given this is a denial-of-service vulnerability in the networking stack, prioritize patching systems exposed to untrusted RPL traffic, particularly those in IoT or constrained network environments.

Recommended fix High confidence

Upgrade to Linux Kernel 5.10.184, 5.15.117, 6.1.34, or 6.2.13 or later (choose the branch appropriate for your distribution)

  1. Identify the currently running kernel version using 'uname -r'
  2. Download or obtain the kernel packages for one of the fixed versions: 5.10.184+, 5.15.117+, 6.1.34+, or 6.2.13+
  3. Install the new kernel packages using the distribution's package manager (e.g., 'dnf install' for RHEL/Fedora, 'apt install' for Debian)
  4. Reboot the system to load the new kernel using 'systemctl reboot'
  5. Verify the system is running the fixed kernel version with 'uname -r'
  6. Ensure RPL protocol functionality is working correctly after reboot
Caveat Kernel upgrades may require rebuilding third-party kernel modules; ensure compatibility with installed drivers 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
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA6.0 h
30.0 hours of engineering $5,120
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Scan for this in your stack

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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-2023-2156 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