What is the CVSS score of EUVD-2025-209647?

EUVD-2025-209647 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.1%.

Which versions of Unisoc IMS are affected by EUVD-2025-209647?

CVE-2025-71251 affects Unisoc chipsets used in mobile devices, allowing remote attackers to trigger complete service denial of the IMS subsystem without authentication.

How to fix or mitigate EUVD-2025-209647?

Within 24 hours: Inventory all mobile devices in deployment using Unisoc chipsets, particularly SC9863A and T-series variants, and identify those with active IMS dependencies. Within 7 days: Coordinate with device manufacturers and Unisoc for patch timelines; implement network-level monitoring for malformed IMS traffic patterns. Within 30 days: Deploy any available vendor security updates as released; evaluate temporary network segmentation of affected devices or disable IMS where operationally feasible pending patch availability.

Unisoc IMS EUVD-2025-209647

| CVE-2025-71251 HIGH

2026-05-06 Unisoc

GHSA-rvm7-7x4c-96v8

Denial Of Service Sc7731E Sc9832E Sc9863A T310 T610 T618 T7200 T7225 T7250 T7255 T7280 T7300 T8100 T9100 T8200 T8300

7.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.5 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

May 06, 2026 - 02:15 vuln.today

DescriptionCVE.org

In IMS, there is a possible system crash due to improper input validation. This could lead to remote denial of service with no additional execution privileges needed.

AnalysisAI

Remote attackers can crash Unisoc chipset IMS (IP Multimedia Subsystem) implementations through network-accessible malformed input, causing complete denial of service with no authentication required. Affects 17 Unisoc chipset models (SC7731E, SC9832E, SC9863A, T-series T310 through T8300) used in mobile devices. CVSS 7.5 (High) reflects direct network exposure and ease of exploitation (AV:N/AC:L/PR:N), though impact is limited to availability. No public exploit code identified at time of analysis, and EPSS data not available for assessment.

Technical ContextAI

IMS (IP Multimedia Subsystem) is the 3GPP standardized framework for delivering voice and multimedia services over IP networks, including VoLTE (Voice over LTE) and Wi-Fi calling. This vulnerability exists in Unisoc's IMS stack implementation across multiple mobile chipset platforms (SC-series and T-series). The root cause involves insufficient input validation when processing network traffic destined for IMS services. Unisoc chipsets are widely deployed in budget and mid-range smartphones, particularly in Asian and emerging markets. The affected CPE indicates platform-level vulnerability spanning 17 distinct chipset models from entry-level (SC7731E) to mid-range (T8300) processors. Without CWE classification, the precise validation failure type is unclear, but network-reachable input validation flaws in IMS typically involve SIP message parsing, SDP negotiation, or XCAP configuration protocols.

RemediationAI

Apply firmware updates from Unisoc or device manufacturers incorporating the IMS input validation fixes for affected chipset models per the vendor security bulletin at https://www.unisoc.com/en/support/product-security-bulletin/2051836844671422466. End users should check with device manufacturers (OEMs) for security updates addressing CVE-2025-71251. If patches are unavailable or delayed, network-level mitigations include restricting IMS traffic to known carrier IP ranges through firewall rules (though this may be impractical for mobile devices), or temporarily disabling VoLTE and Wi-Fi calling features in device settings to reduce IMS attack surface, accepting reduced call quality and fallback to legacy circuit-switched voice. Enterprise mobility management solutions can enforce configuration policies disabling IMS features on managed devices pending patch deployment. For carrier networks, implement anomaly detection for malformed IMS signaling traffic patterns that could indicate exploitation attempts.