CVE-2021-27771

Name: CVE-2021-27771
Creator: NVD / NIST
Published: 2022-05-12T22:15:11.88+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.6/10EPSS 0.67%

Last modified Jun 17, 2026

CVE-2021-27771 is a high-severity vulnerability rated 7.6/10 on the CVSS scale. User SID can be modified resulting in an Arbitrary File Upload or deletion of directories causing a Denial of Service. When interacting in a normal matter with the Sametime chat application, users hold a cookie containing their session ID (SID). EPSS estimates a 0.67% chance of exploitation in the next 30 days.

Description

User SID can be modified resulting in an Arbitrary File Upload or deletion of directories causing a Denial of Service. When interacting in a normal matter with the Sametime chat application, users hold a cookie containing their session ID (SID). This value is also used when sending chat messages, receiving notifications and/or transferring files.

Metrics

CVSS 3.1

7.6/10

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

EPSS Probability

0.67%

47.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Hcltech	Sametime	11.6

References

https://support.hcltechsw.com/csm?id=kb_article&sysparm_article=KB0097430Vendor Advisory
https://support.hcltechsw.com/csm?id=kb_article&sysparm_article=KB0097430Vendor Advisory

Timeline

Published: May 12, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-27771?

How severe is CVE-2021-27771?

CVE-2021-27771 has a CVSS score of 7.6/10 (HIGH severity). The EPSS model estimates a 0.67% probability of exploitation in the next 30 days.

How do I fix CVE-2021-27771?

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-2021-27771?

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

Scan your code now

Source: NVD / NIST