Security Vulnerabilities
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.
CVSS Score
9.3
EPSS Score
0.004
Published
2026-09-17
Transient DOS when processing large or numerous request buffers without sufficient memory allocation validation.
CVSS Score
7.4
EPSS Score
0.002
Published
2026-09-17
Transient DOS when processing unverified data from a neighboring system causes out of bound memory access.
CVSS Score
7.9
EPSS Score
0.001
Published
2026-09-17
Memory Corruption when copying unverified data from an external source exceeds the allocated buffer size.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-09-17
Information Disclosure when a pointer is reused after being deallocated.
CVSS Score
7.3
EPSS Score
0.001
Published
2026-09-17
Memory Corruption when validating large data buffers from external sources using addition to check buffer length.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-09-17
Transient DOS while parsing frame during channel usage.
CVSS Score
7.4
EPSS Score
0.002
Published
2026-09-17
Memory Corruption when multiple threads issue concurrent IOCTL requests to the device control handler due to improper synchronization and race conditions.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-09-17
Transient DOS when processing a channel map with insufficient used channels and adaptive frequency hopping is fully enabled.
CVSS Score
7.4
EPSS Score
0.002
Published
2026-09-17
Memory corruption while processing rear sensor IOCTL calls.
CVSS Score
6.7
EPSS Score
0.001
Published
2026-09-17