SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-55840

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.

MEDIUM 5.4EPSS 0.26%

Does this matter?

Lower severity and a low EPSS score (0.26%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 3.1
5.4 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS
0.26% probability · 18th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-601
Source
security-advisories@github.com
EPSS trend
0%3%5%16 October 2026: 0.26%26 October 2026: 0.26%16 October 202626 October 2026

EPSS moved from 0.3% on 16 October 2026 to 0.3% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.