CVE-2026-54734: Prebid Server Java: Vulnerability to request forgery allows for possible host environment data extraction
Prebid Server Java is the Java version of Prebid Server. Prior to 3.43.0, certain bidder adapters interpolate user-supplied parameters into outbound request URLs without using HttpUtil to validate the resulting domain or path segment. A malicious actor who can supply bid-request parameters can cause the server to send HTTP requests to unintended destinations, potentially reaching internal network services, metadata endpoints, or other sensitive server endpoints with the server's network access. This issue is fixed in version 3.43.0.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Prebid Server Javato a version that resolves this vulnerability.Fixed in 3.43.0
Event History
Frequently Asked Questions
Who can exploit this issue?
An attacker must be able to supply parameters in bid requests processed by a vulnerable Prebid Server Java instance. No authentication or user interaction is required according to the supplied vector.
What systems could be exposed through exploitation?
The server can be induced to make outbound HTTP requests to unintended destinations reachable with its network access. This may include internal network services, cloud metadata endpoints, or other sensitive endpoints accessible from the host environment.
Which versions are affected and what fixes the issue?
Prebid Server Java versions before 3.43.0 are affected. Upgrade to version 3.43.0, which fixes the unsafe URL interpolation in the affected bidder adapters.