What is CVE-2021-27770?

CVE-2021-27770 is a medium-severity vulnerability in Hcl Software Sametime, classified under CWE-472. CVSS score: 6.8/10. Published 2022-05-12.

How severe is CVE-2021-27770?

Medium severity. CVSS v3 base score is 6.8 out of 10.

Vulnerability in Hcl Software Sametime

CVE-2021-27770

The vulnerability was discovered within the “FaviconService”. The service takes a base64-encoded URL which is then requested by the webserver. We assume this service is used by the “meetings”-function where users can specify an external URL where the online meeting will take place.

Published 2022-05-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:L.

EPSS exploit prediction

EPSS: 0.007 (52.2th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: +0.000

Affected products

Hcl Software Sametime — versions 11.6
Hcltech Sametime — versions 11.6

Weakness classification (CWE)

CWE-472

References

support.hcltechsw.com/csm (Vendor Advisory)

Frequently asked questions

What is CVE-2021-27770?: CVE-2021-27770 is a medium-severity vulnerability in Hcl Software Sametime, classified under CWE-472. CVSS score: 6.8/10. Published 2022-05-12.
How severe is CVE-2021-27770?: Medium severity. CVSS v3 base score is 6.8 out of 10.