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Vulnerabilities/CVE-2026-54735Public Intelligence Dossier
Source: prebid · Limited verification•Last verified: •Collection Degraded
CVE-2026-54735Unknown / EvaluatingCRITICAL (raw)CVSS 10.0CWE-918

Prebid Server is an open-source solution for running real-time advertising auctions in the cloud

Published: 29 Jul 2026•Last updated: 24 Oct 2026, 04:40 AM IST•Source identifier: security-advisories@github.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
10.0CRITICAL (raw)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Metric sourcesecurity-advisories@github.com
EPSS probability
0.6%0.006
Percentile49th
Weakness type
CWE-918
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

High Severity / Review

Actively exploited (source statement)

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; CRITICAL severity; Critical source severity without confirmed exploitation

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • prebid prebid server · < 4.4.0 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched ssrf (CWE-918); network-unauthenticated (CVSS AV:N, CVSS PR:N, CVSS UI:N)

Exposure

  1. Identify affected server-side request features and deployed versions.Telemetry: Application inventory · The specific feature must be confirmed from the advisory. · Rule ssrf
  2. Identify devices reporting this CVE and note which expose the affected service to untrusted networks.Telemetry: DeviceTvmSoftwareVulnerabilities · A network-reachable, no-privilege vector makes internet-facing instances the first exposure question. · Rule network-unauthenticated

Exploitation evidence

  1. Review unusual outbound connections from the affected service to internal or metadata endpoints.Telemetry: DeviceNetworkEvents · Outbound patterns can support SSRF hunting. · Rule ssrf
Show more (2)

Exploitation evidence

  1. Review inbound connections to the affected service from unexpected sources since the advisory date.Telemetry: DeviceNetworkEvents · Hunting hypothesis from the CVSS vector; it does not show that exploitation occurred. · Rule network-unauthenticated

Response

  1. Verify the vendor fix and confirm expected egress after deployment.Telemetry: DeviceNetworkEvents · Post-change telemetry helps validate mitigation. · Rule ssrf

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
security-advisories@github.com
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:prebid:prebid_server:*:*:*:*:*:go:*:*

Evidence & Provenance

3 public sources
github.comSource recordnvd.nist.govSource recordgithub.comSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-54735
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-54735
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-54735"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library
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Correlated briefings

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.