CVE-2026-34403Nginx-UI vulnerable to Cross-Site WebSocket Hijacking (CSWSH) via missing origin validation on all WebSocket endpoints
Updated under an hour ago ()
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It affects 0xJacky nginx-ui and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.5 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
- Weakness (CWE)
- CWE-1385
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Analyzed
- Record last updated
- Apr 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
0xJacky nginx-ui 0xjacky:nginx_ui (from the name) | before 2.3.5 | CNA record |
nginxui nginx_ui nginxui:nginx_ui | before 2.3.5 | NVD |
References
- https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-78mf-482w-62qjx-refsource-confirm, exploit, mitigation, vendor-advisory
- https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.5x-refsource-misc, product, release-notes
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.