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prebid-server's request forgery vulnerability allows for possible host environment data extraction

Critical severity GitHub Reviewed Published Jun 8, 2026 in prebid/prebid-server

Package

gomod github.com/prebid/prebid-server (Go)

Affected versions

<= 0.275.0

Patched versions

None
gomod github.com/prebid/prebid-server/v2 (Go)
<= 2.32.0
None
gomod github.com/prebid/prebid-server/v3 (Go)
<= 3.30.0
None
gomod github.com/prebid/prebid-server/v4 (Go)
< 4.4.0
4.4.0

Description

Impact

Certain bidder adapters accept user-supplied parameters that are interpolated into outbound request URLs. Without proper input validation, a malicious actor could craft bid request parameters that cause the server to send HTTP requests to unintended destinations, potentially exposing internal network services or sensitive server endpoints to unauthorized access.

Patches

Patched in v4.4.0

Workarounds

If one is unable to update, please make sure that the affected bidder adapters are disabled.

References

@bsardo bsardo published to prebid/prebid-server Jun 8, 2026
Published to the GitHub Advisory Database Jul 29, 2026
Reviewed Jul 29, 2026

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS score

Weaknesses

Server-Side Request Forgery (SSRF)

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Learn more on MITRE.

CVE ID

CVE-2026-54735

GHSA ID

GHSA-4p3g-4hcj-wpvx

Source code

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