CVE-2026-54735

critical

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.

References

https://github.com/prebid/prebid-server/security/advisories/GHSA-4p3g-4hcj-wpvx

https://github.com/prebid/prebid-server/releases/tag/v4.4.0

https://github.com/prebid/prebid-server/pull/4802

https://github.com/prebid/prebid-server/commit/494ac271cd4b5024df9123ef25ca3cff96390be3

Details

Source: Mitre, NVD

Published: 2026-07-29

Updated: 2026-07-30

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 10

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

Severity: Critical

EPSS

EPSS: 0.00351