CVE-2026-54735
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.34%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 0.34% probability · 28th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-918
- Affected
- prebid/prebid server
- Source
- security-advisories@github.com
References
- https://github.com/prebid/prebid-server/commit/494ac271cd4b5024df9123ef25ca3cff96390be3Patch
- https://github.com/prebid/prebid-server/pull/4802Issue Tracking, Patch
- https://github.com/prebid/prebid-server/releases/tag/v4.4.0Product, Release Notes
- https://github.com/prebid/prebid-server/security/advisories/GHSA-4p3g-4hcj-wpvxPatch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.