CVE-2021-20875

Name: CVE-2021-20875
Creator: NVD / NIST
Published: 2021-12-24T07:15:06.747+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.82%

Last modified Jun 17, 2026

CVE-2021-20875 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. Open redirect vulnerability in GroupSession Free edition ver5.1.1 and earlier, GroupSession byCloud ver5.1.1 and earlier, and GroupSession ZION ver5.1.1 and earlier allows a remote unauthenticated attacker to redirect users to arbitrary web sites and conduct phishing attacks by having a user to access a specially crafted URL.. EPSS estimates a 0.82% chance of exploitation in the next 30 days.

Description

Open redirect vulnerability in GroupSession Free edition ver5.1.1 and earlier, GroupSession byCloud ver5.1.1 and earlier, and GroupSession ZION ver5.1.1 and earlier allows a remote unauthenticated attacker to redirect users to arbitrary web sites and conduct phishing attacks by having a user to access a specially crafted URL.

Metrics

CVSS 3.1

6.1/10

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

EPSS Probability

0.82%

52.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-601

Affected Software

Vendor	Product	Versions
Groupsession	Groupsession	<= 5.1.1

References

https://groupsession.jp/info/info-news/security20211220Vendor Advisory
https://jvn.jp/en/jp/JVN79798166/index.htmlThird Party Advisory
https://groupsession.jp/info/info-news/security20211220Vendor Advisory
https://jvn.jp/en/jp/JVN79798166/index.htmlThird Party Advisory

Timeline

Published: Dec 24, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20875?

How severe is CVE-2021-20875?

CVE-2021-20875 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.82% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20875?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20875?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST