SSRF in Prebid Prebid-Server
CVE-2026-54735
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.
Vulnerability class: SSRF (Server-Side Request Forgery)
EPSS: 0.003 (27.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
Affected products
- Prebid Prebid-server — versions < 4.4.0
- Prebid Prebid_server
Weakness classification (CWE)
References
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-54735?
- CVE-2026-54735 is a critical-severity vulnerability in Prebid Prebid-Server, classified under Server-Side Request Forgery (SSRF). CVSS score: 10.0/10. Published 2026-07-29.
- How severe is CVE-2026-54735?
- Critical severity. CVSS v3 base score is 10.0 out of 10.