Vulnerability · Published Oct 15, 2026 · Assigned by GitHub_M

CVE-2026-55840Scoold: Open Redirect in getBackToUrl() allows phishing via domain-prefix startsWith bypass

Medium 5.4

In plain English

A medium-severity open redirect in scoold from Erudika. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 18% of all known vulnerabilities).

Severity (CVSS 3.1)5.4Medium

Exploit odds (30 days)0.3%top 81.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
Erudika	scoold	< 1.69.1

Weakness: CWE-601 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

References

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