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Contiki NgOperating system

CVE-2022-41972

MEDIUM · 6.5 CVSS v3.1 Published 2022-12-16
Fix available
A fix is available. Upgrade to after 4.8 or later.
See remediation →
70/100
Remediation priority · Elevated
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
Contiki-NG is an open-source, cross-platform operating system for Next-Generation IoT devices. Versions prior to 4.9 contain a NULL Pointer Dereference in BLE L2CAP module. The Contiki-NG operating system for IoT devices contains a Bluetooth Low Energy stack. An attacker can inject a packet in this stack, which causes the implementation to dereference a NULL pointer and triggers undefined behavior. More specifically, while processing the L2CAP protocol, the implementation maps an incoming channel ID to its metadata structure. In this structure, state information regarding credits is managed through calls to the function input_l2cap_credit in the module os/net/mac/ble/ble-l2cap.c. Unfortunately, the input_l2cap_credit function does not check that the metadata corresponding to the user-supplied channel ID actually exists, which can lead to the channel variable being set to NULL before a pointer dereferencing operation is performed. The vulnerability has been patched in the "develop" branch of Contiki-NG, and will be included in release 4.9. Users can apply the patch in Contiki-NG pull request #2253 as a workaround until the new package is released.

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
How this class of weakness works · CWE-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
Contiki NgOperating system
Affected:<= 4.8

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

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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 a release after 4.8
Vendor patch github.com →
Recommended fix High confidence

4.9

  1. Identify the current Contiki-NG version in use by checking the version file or git tag
  2. Obtain Contiki-NG version 4.9 from the official repository at https://github.com/contiki-ng/contiki-ng
  3. Update the Contiki-NG installation by replacing the existing files with version 4.9 files
  4. Verify that the BLE L2CAP module (os/net/mac/ble/ble-l2cap.c) has been updated with the fix from PR #2253 which adds the NULL check in the input_l2cap_credit function
  5. Rebuild the firmware with the updated Contiki-NG version

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

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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-2022-41972 in production — separate from our analysis above.

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What this is

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