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.
Affected products
prebid: prebid server
References4
- github.com/prebid/prebid-server/security/advisories/GHSA-4p3g-4… PatchVendor Advisory
- github.com/prebid/prebid-server/commit/494ac271cd4b5024df9123ef… Patch
- github.com/prebid/prebid-server/pull/4802 Issue TrackingPatch
- github.com/prebid/prebid-server/releases/tag/v4.4.0 ProductRelease Notes
Metrics
- CVSS 3.1
-
10.0
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 50 · as of 13 November 2026
- CWE
- CWE-918
Could this be exploited in your environment?
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