Critical Authentication

CVE-2026-86863 — Authentication Bypass by Spoofing in Pgadmin Pgadmin 4

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.

Published Sep 17, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database · CNA: f86ef6dc-4d3a-42ad-8f28-e6d5547a5007

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (critical)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Pgadmin

Pgadmin 4

CVSS base

9.8

Critical · 1 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Pgadmin Pgadmin 4).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Pgadmin	Pgadmin 4	≥ 6.2 and < 9.18	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
9.3	CVSS 4.0	Critical	—	—	f86ef6dc-4d3a-42ad-8f28-e6d5547a5007 via NIST National Vulnerability Database
9.8	CVSS 3.1	Critical	3.9	5.9	f86ef6dc-4d3a-42ad-8f28-e6d5547a5007 via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: f86ef6dc-4d3a-42ad-8f28-e6d5547a5007)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-290 · Authentication Bypass by Spoofing

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.

web/proxy/WAF logsnetwork IDS/IPSauthentication logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Fix documented
Oct 15, 2026 · NIST National Vulnerability Database
CVSS changed · 9.8
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 17, 2026 · f86ef6dc-4d3a-42ad-8f28-e6d5547a5007

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

1 on the record

github.com/pgadmin-org/pgadmin4/issues/10383
Issue Tracking, Patch, Vendor Advisory, NIST National Vulnerability Database

Elsewhere on this site

Pgadmin
every CVE for this vendor

Authentication
same class

CWE-290
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-86864 Path Traversal in Pgadmin Pgadmin 4 28d
Medium CVE-2026-86861 Link Following in Pgadmin Pgadmin 4 28d
Medium CVE-2026-86862 Argument Injection in Pgadmin Pgadmin 4 28d
Critical CVE-2026-17566 pgAdmin 4: RCE via backslash-escape mismatch in Import/Export Data query guard (incomplete defense, sibling gap to CVE-2025-13780) Jul 31, 2026
Medium CVE-2026-17348 pgAdmin 4: Missing authentication decorator on Constraints, preferences, Debugger and Schema Diff routes allows unauthenticated access in SERVER mode (incomplete fix for CVE-2026-12046) Jul 31, 2026
High CVE-2026-17347 pgAdmin 4: OS command injection in MASTER_PASSWORD_HOOK via untrusted username substitution Jul 31, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No CISA SSVC assessment.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-86863 is "Authentication Bypass by Spoofing in Pgadmin Pgadmin 4", rated Critical. It affects Pgadmin 4 (Pgadmin); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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