CVE-2026-93649: eclipse foundation adoptium temurin Download of Code Without Integrity Check

Vulnerability summary

CVE-2026-93649 is a high (CVSS 7.5) Download of Code Without Integrity Check vulnerability in eclipse foundation adoptium temurin. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 4.2% of scored vulnerabilities.

Timeline

1. 15-10-2026
   PublishedVulnerability first disclosed.
2. 16-10-2026
   Last modifiedVulnerability information updated.

Description

In the Eclipse Adoptium website (adoptium.net), in every deployment built from commit 0b24ea1 (2025-06-18) up to the fix in commit cbb53cf (2026-09-24), the post-download page /[locale]/download takes a download URL from the "link" query parameter and automatically navigates to it with a meta http-equiv="refresh". The URL is checked against a list of trusted prefixes using String.startsWith() on the raw string, while the browser applies RFC 3986 dot-segment normalisation before navigating, so a value such as https://github.com/adoptium/temurin/../../attacker/malware/releases/download/v1/jdk.exe passes the check but resolves to an attacker-controlled repository. A victim who follows a crafted adoptium.net link is shown the genuine "Thank you for downloading Eclipse Temurin" page while their browser downloads a binary of the attacker's choosing

• CWE-494Download of Code Without Integrity CheckThe product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.
• CWE-601URL Redirection to Untrusted Site ('Open Redirect')The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.