CVE-2026-54735 — CRITICAL (10.0)

Vulnerability Description

Prebid Server is an open-source solution for running real-time advertising auctions in the cloud. Prior to version 4.4.0, certain bidder adapters in Prebid Server interpolate user-supplied parameters into outbound request URLs without properly validating host and subdomain values, allowing crafted bid request parameters to cause server-side requests to unintended destinations and potentially expose internal network services or sensitive server endpoints. This issue is fixed in version 4.4.0.

CVSS Score

10.0

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Related Weaknesses (CWE)

CWE-918

References

FAQ

What is CVE-2026-54735?

CVE-2026-54735 is a vulnerability with a CVSS score of 10.0 (CRITICAL). Prebid Server is an open-source solution for running real-time advertising auctions in the cloud. Prior to version 4.4.0, certain bidder adapters in Prebid Server interpolate user-supplied parameters ...

How severe is CVE-2026-54735?

CVE-2026-54735 has been rated CRITICAL with a CVSS base score of 10.0/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-54735?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.