Categories
CVE-2026-54735 critical CVSS 10.0

SSRF (Server-Side Request Forgery) in github.com/prebid/prebid-server/v4 (CVE-2026-54735)

Summary

SSRF in github.com/prebid/prebid-server/v4 (CVE-2026-54735). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 4.4.0 or later.

Original description

The description as published by the source.

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

Workarounds

If one is unable to update, please make sure that the affected bidder adapters are disabled.

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-54735 has been found in github.com/prebid/prebid-server/v4.
Successful exploitation can lead to full system takeover. CVSS score: 10.0/10.
What to do: upgrade github.com/prebid/prebid-server/v4 to 4.4.0 or later.
If unsure, ask your IT team or search "github.com/prebid/prebid-server/v4 CVE-2026-54735" on the vendor's site.

CVE-2026-54735 (github.com/prebid/prebid-server/v4) — CWE-918 / CVSS v3 10.0
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 4.4.0 — apply immediately
Workaround: If one is unable to update, please make sure that the affected bidder adapters are disabled.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

SSRF (CWE-918) exists in github.com/prebid/prebid-server/v4.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/prebid/prebid-server/v4.

🔥 Severity

Severity: Critical (CVSS 10.0/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 4.4.0.

🛡️ Workaround

Workaround: If one is unable to update, please make sure that the affected bidder adapters are disabled.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/prebid/prebid-server/v4' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify
    grep -r 'github.com/prebid/prebid-server/v4' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で github.com/prebid/prebid-server/v4 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply temporary workaround mitigate
    If one is unable to update, please make sure that the affected bidder adapters are disabled.

    パッチが適用されるまでの応急処置として、If one is unable to update, please make sure that the affected bidder adapters are disabled. を実施。回避策の副作用 (機能低下) を確認した上で。

  3. 3
    Apply patch patch
    Upgrade github.com/prebid/prebid-server/v4 to 4.4.0

    ステージング環境で 4.4.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  4. 4
    Post-deployment verification verify
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

go github.com/prebid/prebid-server/v4
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.4.0"}]}]
go github.com/prebid/prebid-server/v3
[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"3.30.0"}]}]
go github.com/prebid/prebid-server/v2
[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"2.32.0"}]}]
go github.com/prebid/prebid-server
[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"0.275.0"}]}]

References

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