0xJacky nginx-ui up to 2.3.4 gorilla/websocket missing origin validation in websockets

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.1$0-$5k0.26

Summaryinfo

A vulnerability was found in 0xJacky nginx-ui up to 2.3.4. It has been classified as problematic. This affects an unknown function of the component gorilla/websocket. Performing a manipulation results in missing origin validation in websockets. This vulnerability is reported as CVE-2026-34403. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in 0xJacky nginx-ui up to 2.3.4. It has been classified as problematic. This affects an unknown code block of the component gorilla/websocket. The manipulation with an unknown input leads to a missing origin validation in websockets vulnerability. CWE is classifying the issue as CWE-1385. The product uses a WebSocket, but it does not properly verify that the source of data or communication is valid. This is going to have an impact on integrity. The summary by CVE is:

Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.5, all WebSocket endpoints in nginx-ui use a gorilla/websocket Upgrader with CheckOrigin unconditionally returning true, allowing Cross-Site WebSocket Hijacking (CSWSH). Combined with the fact that authentication tokens are stored in browser cookies (set via JavaScript without HttpOnly or explicit SameSite attributes), a malicious webpage can establish authenticated WebSocket connections to the nginx-ui instance when a logged-in administrator visits the attacker-controlled page. Version 2.3.5 patches the issue.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-34403 since 03/27/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available.

Upgrading to version 2.3.5 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1188). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Open Source nginx-ui

Productinfo

Type

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Missing origin validation in websockets
CWE: CWE-1385 / CWE-346 / CWE-345
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: nginx-ui 2.3.5

Timelineinfo

03/27/2026 CVE reserved
04/21/2026 +24 days Advisory disclosed
04/21/2026 +0 days VulDB entry created
04/22/2026 +1 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-78mf-482w-62qj
Status: Confirmed

CVE: CVE-2026-34403 (🔒)
GCVE (CVE): GCVE-0-2026-34403
GCVE (VulDB): GCVE-100-358377
CERT Bund: WID-SEC-2026-1188 - nginx-ui: Mehrere Schwachstellen ermöglichen Umgehen von Sicherheitsvorkehrungen

Entryinfo

Created: 04/21/2026 06:51
Updated: 04/22/2026 02:15
Changes: 04/21/2026 06:51 (69), 04/22/2026 02:15 (7)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!