Prebid Server Java: Vulnerability to request forgery allows for possible host environment data extraction

published 2026-09-17 52 d ago modified 2026-09-23 46 d ago also EUVD-2026-82581

cvss: 10.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits: 0; none known

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.

Patch / fix

links 4

github.com/prebid/prebid-server-java@a129a68 commit
github.com/prebid/prebid-server-java@d0c723c commit
github.com/prebid/prebid-server-java#4522 pull request
github.com/prebid/prebid-server-java/releases/tag/3.43.0 release

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 51 d ago (2026-09-18)

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	10.0	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

prebid prebid-server-java

Classification

Weakness

CWE-918 Server-Side Request Forgery

References

Sources

CVE List CVE-2026-54734
NVD CVE-2026-54734

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary