CVE-2026-42800: High-Severity Null Pointer Dereference in ASR Lapwing_Linux
The National Vulnerability Database has disclosed CVE-2026-42800, a critical NULL pointer dereference vulnerability impacting ASR Lapwing_Linux on Linux systems. This flaw, located in the sipuri.c file within the ims_client modules, allows for pointer manipulation. With a CVSS score of 7.4 (HIGH), this vulnerability presents a significant risk to systems running the affected software.
Attackers can leverage this weakness remotely with low complexity and no privileges required, potentially leading to denial of service or even code execution depending on the dereferenced pointer. The National Vulnerability Database has not specified affected products beyond the general operating environment, underscoring the need for broad vigilance.
Defenders should prioritize identifying and patching any instances of ASR Lapwing_Linux on Linux. Where patching is not immediately feasible, network segmentation and strict access controls are crucial to limit the attack surface. Auditing for unusual network activity or system instability related to the ims_client modules should also be implemented.
What This Means For You
- If your organization utilizes ASR Lapwing_Linux on Linux, immediately investigate its presence and apply any available security patches for CVE-2026-42800. Audit system logs for suspicious pointer activity or crashes within the `ims_client` modules.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-42800: ASR Lapwing_Linux Null Pointer Dereference via SIP URI Manipulation
title: CVE-2026-42800: ASR Lapwing_Linux Null Pointer Dereference via SIP URI Manipulation
id: scw-2026-04-30-ai-1
status: experimental
level: critical
description: |
This rule detects attempts to exploit CVE-2026-42800 by targeting the sip/utils/src/sipuri.c file within ASR Lapwing_Linux. The vulnerability, a null pointer dereference, is triggered by specific pointer manipulation, likely through crafted SIP URIs. This detection focuses on suspicious URI patterns that directly reference the vulnerable component and include a placeholder for exploit-specific query parameters.
author: SCW Feed Engine (AI-generated)
date: 2026-04-30
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-42800/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/sip/utils/src/sipuri.c'
cs-uri-query|contains:
- 'null_pointer_dereference_exploit'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-42800 | Vulnerability | CVE-2026-42800 |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | April 30, 2026 at 13:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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