CVE-2025-71251: IMS DoS Vulnerability Poses High Risk
The National Vulnerability Database (NVD) has disclosed CVE-2025-71251, a high-severity vulnerability affecting IMS (IP Multimedia Subsystem) with a CVSS score of 7.5. This flaw stems from improper input validation, which can lead to a system crash. The critical aspect here is the potential for a remote denial-of-service (DoS) attack, requiring no additional execution privileges.
This isn’t just a theoretical bug. Attackers can exploit this remotely, bringing down critical IMS services without needing to escalate privileges or bypass complex authentication. For any organization relying on IMS for voice, video, or messaging services, this vulnerability represents a direct threat to operational continuity and service availability. The lack of specific affected products from NVD means defenders need to assume a broad impact across IMS implementations.
CISOs must recognize the severity of a remote DoS. It’s a low-effort, high-impact attack vector. While the NVD has not specified affected products, it’s prudent to review all IMS components and configurations. Prioritize vendor communications for patches or mitigation strategies. The attacker’s calculus is simple: find an exposed IMS endpoint, send malformed input, and disrupt service. Defenders need to make that calculus much harder.
What This Means For You
- If your organization utilizes IMS for critical communications, this vulnerability is a direct threat to your uptime. Immediately identify all IMS deployments within your infrastructure and engage with your vendors to ascertain exposure to CVE-2025-71251. Prioritize patching or implementing compensating controls to prevent remote denial-of-service.
Related ATT&CK Techniques
🛡️ Detection Rules
2 rules · 6 SIEM formats2 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-2025-71251: IMS DoS - Malformed SIP Request
title: CVE-2025-71251: IMS DoS - Malformed SIP Request
id: scw-2026-05-06-ai-1
status: experimental
level: high
description: |
Detects a potential exploit attempt for CVE-2025-71251 by looking for malformed SIP requests targeting the IMS service, indicated by specific URI patterns and a server error response. This rule aims to catch the initial exploitation attempt that could lead to a denial of service.
author: SCW Feed Engine (AI-generated)
date: 2026-05-06
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2025-71251/
tags:
- attack.impact
- attack.t1499
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/ims/sip'
cs-uri-query|contains:
- 'invalid_header_value'
sc-status:
- 500
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2025-71251 | DoS | IMS |
| CVE-2025-71251 | DoS | improper input validation |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 06, 2026 at 05:16 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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