GHSA-4p3g-4hcj-wpvxPublished

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

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-54735

Published

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.

Source published: 29 Jul 2026 15:59:46 UTC
Source modified: 29 Jul 2026 18:04:18 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

nvd · CVE-2026-54735

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-918

Original publisher date fields

published: 2026-07-29T16:17:54.317

lastModified: 2026-10-23T23:10:00.157

1 source CPE criteria · context only

cpe:2.3:a:prebid:prebid_server:*:*:*:*:*:go:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 29 Jul 2026 16:17:54 UTC
Source modified: 23 Oct 2026 23:10:00 UTC
Observed here: 25 Oct 2026 13:17:34 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

osv · GHSA-4p3g-4hcj-wpvx

Published

### Impact Certain bidder adapters accept user-supplied parameters that are interpolated into outbound request URLs. Without proper input validation, a malicious actor could craft bid request parameters that cause the server to send HTTP requests to unintended destinations, potentially exposing internal network services or sensitive server endpoints to unauthorized access. ### Patches Patched in [v4.4.0](https://github.com/prebid/prebid-server/releases/tag/v4.4.0) ### Workarounds If one is unable to update, please make sure that the affected bidder adapters are disabled.

Source published: 29 Jul 2026 16:00:36 UTC
Source modified: 18 Aug 2026 17:23:47 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Publisher rating · CRITICAL

osv · GO-2026-6139

Published

In github.com/prebid/prebid-server/v4 before 4.4.0, multiple bidder adapters (acuityads, bidmachine, relevantdigital, smartyads, tappx, trafficgate, zeroclickfraud) interpolate user-supplied host and subdomain parameters into outbound request URLs without validation. A remote attacker can craft bid request parameters containing path traversals or target addresses to trigger server-side request forgery (SSRF), sending HTTP requests to internal network services or unintended endpoints.

Source published: 18 Aug 2026 16:38:10 UTC
Source modified: 18 Aug 2026 17:15:27 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.