CVE-2026-54735

prebid-server's request forgery vulnerability allows for possible host environment data extraction

CRITICAL
10
CVSS Score
Published: July 29, 2026 at 03:59 PM UTC
Updated: October 23, 2026 at 11:10 PM UTC
1 product affected across 1 vendorPrebid Server

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Severity
CRITICAL10
Exploit prediction
EPSS 0.6%
SSVC
No known 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.4.0
Affected range stops below 4.4.0, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMPatchVendor Advisory
Source: cverecord
https://github.com/prebid/prebid-server/security/advisories/GHSA-4p3g-4hcj-wpvx
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/prebid/prebid-server/pull/4802
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/prebid/prebid-server/releases/tag/v4.4.0

SSVC — Action Prioritization

SSVCNo known exploitAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

10CRITICALGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-918

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