CVE-2026-86863

pgAdmin 4's Webserver authentication source is intended to accept an identity asserted by the web server or reverse proxy in front of pgAdmin, delivered through the WSGI/CGI environment. WebserverAuthentication.get_user() read config.WEBSERVER_REMOTE_USER from request.environ and, when that returned nothing, fell back to reading the same name directly from the inbound HTTP request headers via request.headers.get(). An inbound HTTP header is written by whoever sends the request, so any client able to reach pgAdmin could supply that header itself and be authenticated as any username it named, including an existing Administrator, without presenting a password or any other credential. The environment lookup could also be satisfied by a client-supplied header whenever WEBSERVER_REMOTE_USER was configured to an HTTP_-prefixed or hyphenated name such as HTTP_X_FORWARDED_USER or X-Forwarded-User, since WSGI servers place inbound headers into the environment under exactly those names. Deployments are affected only when 'webserver' is enabled in AUTHENTICATION_SOURCES. The fix distinguishes a genuine CGI/WSGI variable from a header-derived one and implicitly trusts only the former. A header-asserted identity is now accepted only when the operator explicitly opts in via WEBSERVER_REMOTE_USER_FROM_HEADER, the request arrives from a peer listed in WEBSERVER_TRUSTED_PROXIES, and, when configured, a shared secret supplied in WEBSERVER_SHARED_SECRET_HEADER matches WEBSERVER_SHARED_SECRET under a constant-time comparison. The trusted-peer check deliberately reads the real socket peer address rather than request.remote_addr, because ProxyFix rewrites the latter from the client-controlled X-Forwarded-For header and would otherwise allow an attacker to claim to be the trusted proxy. As defence in depth, login() now refuses any account whose auth_source is not 'webserver', so a misconfigured trust gate cannot be used to assume an internal or LDAP account. This issue affects pgAdmin 4: from 6.2 before 9.18.

• CWE-290
• CWE-807

• https://github.com/pgadmin-org/pgadmin4/issues/10383Issue Tracking, Patch, Vendor Advisory

Published

Sep 17, 2026

Last Modified

Sep 21, 2026

Status

Analyzed

• Same Subject, Wrong User: A Cross-Issuer Account Takeover in n8nStrix found an identity-binding bug in n8n's token-exchange flow enabling account takeover.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-86840The `vtoken-minting` and `slpx` pallets in Bifrost contain a…9.1
• CVE-2026-8685The Infility Global plugin for WordPress is vulnerable to SQ…6.5
• CVE-2026-86853A malicious webpage could repeatedly trigger external URL sc…4.3
• CVE-2026-8686Missing bounds validation in the MQTT v5.0 property parser i…9.1
• CVE-2026-86861pgAdmin 4's File Manager save_file endpoint, which backs sav…5.9
• CVE-2026-86862pgAdmin 4's Restore and Maintenance tools passed the client-…6.5
• CVE-2026-86864pgAdmin 4's Backup tool appended the client-supplied 'databa…8.8
• CVE-2026-86865Tanium addressed a SQL injection vulnerability in Asset.7.2
• CVE-2026-86869An out-of-bounds write issue was addressed with improved bou…6.5
• CVE-2026-86870A heap buffer overflow was addressed with improved bounds ch…6.5
• CVE-2026-86876An out-of-bounds write issue was addressed with improved bou…5.2
• CVE-2026-86878A permissions issue was addressed with additional restrictio…5.5