CVE-2026-55840: Scoold: Open Redirect in getBackToUrl() allows phishing via domain-prefix startsWith bypass
Scoold is a Q&A and a knowledge sharing platform for teams. Prior to 1.69.1, the getBackToUrl() method in src/main/java/com/erudika/scoold/utils/HttpUtils.java validates the backto and returnto parameters with Strings.CI.startsWith against the configured server URL. An attacker can supply an absolute URL whose hostname begins with the legitimate hostname, causing URI.resolve() to retain the attacker URL and the prefix check to accept it. A victim who follows the crafted sign-in link can be redirected to an attacker-controlled domain after authentication, enabling phishing and possible credential or token theft. This issue is fixed in version 1.69.1.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Scooldto a version that resolves this vulnerability.Fixed in 1.69.1
Event History
Frequently Asked Questions
Which deployments are affected?
Scoold versions prior to 1.69.1 are affected. The vulnerable behavior applies to sign-in links that process the backto or returnto parameters against the configured server URL.
What does an attacker need to exploit this issue?
An attacker needs to craft a sign-in link containing an absolute attacker-controlled URL whose hostname starts with the legitimate hostname, then persuade a victim to follow it. No attacker authentication is required, but victim interaction is required.
What is the impact after a victim uses a crafted link?
After authentication, the victim can be redirected to an attacker-controlled domain. This can support phishing and possible theft of credentials or tokens.
How can the issue be remediated?
Upgrade Scoold to version 1.69.1, which fixes the URL validation flaw.