CVE-2026-55840: Open Redirect (CVSS 5.4)

Description

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.

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CVSS v3.1 Score

5.4

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0026

Probability of exploitation

0.18%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-601 CWE-601

References

Other References

https://github.com/Erudika/scoold/commit/9d61f6fe15d4f9f6262812ba7fea43be8d5bb745 https://github.com/Erudika/scoold/releases/tag/1.69.1 https://github.com/Erudika/scoold/security/advisories/GHSA-85fm-6f2v-74pq https://github.com/Erudika/scoold/security/advisories/GHSA-85fm-6f2v-74pq

Frequently Asked Questions

What is CVE-2026-55840? +

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. It has a CVSS v3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2026-55840? +

CVE-2026-55840 has a CVSS v3.1 score of 5.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-55840? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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