Vulnerability · Published Sep 17, 2026 · Assigned by GitHub_M

CVE-2026-54734Prebid Server Java: Vulnerability to request forgery allows for possible host environment data extraction

Critical 10.0

In plain English

A critical-severity server-side request forgery in prebid-server-java from prebid. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities).

Severity (CVSS 3.1)10.0Critical

Exploit odds (30 days)0.6%top 50.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Prebid Server Java is the Java version of Prebid Server. Prior to 3.43.0, certain bidder adapters interpolate user-supplied parameters into outbound request URLs without using HttpUtil to validate the resulting domain or path segment. A malicious actor who can supply bid-request parameters can cause the server to send HTTP requests to unintended destinations, potentially reaching internal network services, metadata endpoints, or other sensitive server endpoints with the server's network access. This issue is fixed in version 3.43.0.

Affected products (as reported)

Vendor	Product	Versions
prebid	prebid-server-java	< 3.43.0

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

References

https://github.com/prebid/prebid-server-java/security/advisories/GHSA-fr2c-g2f8-qchg x_refsource_CONFIRM
https://github.com/prebid/prebid-server-java/pull/4522 x_refsource_MISC
https://github.com/prebid/prebid-server-java/commit/a129a685b6fc54441c1a779ce29ea4ec20c2e09f x_refsource_MISC
https://github.com/prebid/prebid-server-java/commit/d0c723ce36aa09712c825ea9625d978f45d29a1c x_refsource_MISC
https://github.com/prebid/prebid-server-java/releases/tag/3.43.0 x_refsource_MISC