How severe is CVE-2021-27770?

CVE-2021-27770 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity low, and availability low.

Is CVE-2021-27770 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27770?

CVE-2021-27770 affects Hcltech Sametime. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27770?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-27770 published?

CVE-2021-27770 was published on 2022-05-12 and last updated on 2026-06-17.

CVE-2021-27770

CVE-2021-27770 is a medium-severity vulnerability in Hcltech Sametime with a CVSS 3.x base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-472.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-472
Affected product: Hcltech Sametime
Published: 2022-05-12
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-27770?: CVE-2021-27770 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity low, and availability low.
Is CVE-2021-27770 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27770?: CVE-2021-27770 affects Hcltech Sametime. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27770?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-27770 published?: CVE-2021-27770 was published on 2022-05-12 and last updated on 2026-06-17.

References

https://support.hcltechsw.com/csm?id=kb_article&sysparm_article=KB0097430

Affected products (1)

cpe:2.3:a:hcltech:sametime:11.6:*:*:*:*:*:*:*

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