What is the CVSS score of CVE-2026-52191?

CVE-2026-52191 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: 0.2%.

Which versions of UTT nv518G are affected by CVE-2026-52191?

The UTT nv518G security gateway/router (firmware nv518GV3v3.2.7 and earlier) contains an unauthenticated remote denial-of-service vulnerability that allows attackers to crash the device without…

How to fix or mitigate CVE-2026-52191?

Within 24 hours: Identify all UTT nv518G units on network and document firmware versions, particularly nv518GV3v3.2.7-210919-161313; restrict management interface access to trusted administrative networks only and disable external web management access if not operationally required. Within 7 days: Implement network segmentation to isolate management interfaces; enable connection rate-limiting and access logging on management ports; document device recovery procedures. Within 30 days: Contact UTT vendor for patch timeline; evaluate replacement with actively-supported security gateway alternatives; implement enhanced monitoring for device availability anomalies.

UTT nv518G CVE-2026-52191

HIGH

Classic Buffer Overflow (CWE-120)

2026-07-02 mitre

Buffer Overflow Denial Of Service N A

7.5

CVSS 3.1 · Vendor: mitre

Severity by source

Vendor (mitre) PRIMARY

7.5 HIGH

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

vuln.today AI

7.5 HIGH

Unauthenticated, low-complexity HTTP request reachable over the network with no user interaction (AV:N/AC:L/PR:N/UI:N); impact is a service/device crash only, so C:N/I:N/A:H.

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

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (mitre).

CVSS VectorVendor: mitre

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

Jul 06, 2026 - 16:27 vuln.today

CVSS changed

Jul 06, 2026 - 16:22 NVD

7.5 (HIGH)

CVE Published

Jul 02, 2026 - 00:00 cve.org

UNKNOWN (no severity yet)

DescriptionCVE.org

Buffer Overflow vulnerability in UTT nv518G nv518GV3v3.2.7-210919-161313 allows a remote attacker to cause a denial of service via the gohead/sub_444C8C component

AnalysisAI

Remote denial of service in the UTT nv518G security gateway/router (firmware nv518GV3v3.2.7-210919-161313) allows an unauthenticated attacker to crash the device by triggering a buffer overflow in the gohead/sub_444C8C function of its embedded web management service. The flaw impacts availability only - no code execution, data disclosure, or integrity loss is indicated - and CVSS rates it 7.5 (High). No public exploit identified at time of analysis, though a GitHub reverse-engineering report documents the vulnerable function; EPSS is low at 0.22% (13th percentile) and it is not on the CISA KEV list.

Technical ContextAI

The affected component is the 'gohead' web service on a UTT nv518G - 'gohead' is characteristic of the GoAhead-style embedded HTTP server used in SOHO/SMB networking appliances, where request handling is written in C with manual buffer management. The vulnerable routine is identified only by its disassembly address (sub_444C8C / FUN_00444c8c), consistent with the flaw being found through static reverse engineering of the firmware binary rather than source review. The root cause maps to CWE-120 (Classic Buffer Overflow / copy without bounds check): attacker-controlled input from an HTTP request is copied into a fixed-size stack or heap buffer without validating its length, corrupting adjacent memory and crashing the service process.

RemediationAI

No vendor-released patch identified at time of analysis; check the UTT download center (https://utt.com.cn/downloadcenter.php?filetypeid=3&model=518G&lang=zhcn) for a firmware build newer than nv518GV3v3.2.7-210919-161313 and apply it once published. As compensating controls, restrict access to the device's web management interface: bind management to the LAN only and disable remote/WAN administration (trade-off: administrators lose off-site management convenience and must use VPN), and place ACLs or a firewall rule blocking inbound HTTP/HTTPS to the gateway's management port from untrusted networks (trade-off: none for external users, but ensure legitimate management hosts remain permitted). Where feasible, front the management port with a reverse proxy or source-IP allowlist so only known admin workstations can reach gohead. Monitor for unexpected device reboots/hangs as an indicator of exploitation attempts.