CVE-2021-27770
HCL Sametime is vulnerable to arbitrary HTTP requests
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
HCL Sametime is vulnerable to arbitrary HTTP requests
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.
- Record
CVE-2021-27770- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:L - Weakness
- CWE-472
- Updated
- 2026-11-02
EUVDEUVD-2021-14511
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.
- Record
EUVD-2021-14511- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:L - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-mxvv-v7w8-j88h
The vulnerability was discovered within the “FaviconService”. The service takes a base64-encoded...
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.
- Record
GHSA-mxvv-v7w8-j88h- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-472, CWE-668
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-27770- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:L - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.8 Medium
AV:N/AC:M/Au:N/C:P/I:P/A:P - Weakness
- CWE-472
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27770 is a medium vulnerability (CVSS 6.8) in Hcl Sametime, published May 12, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.74%, the 54th percentile. No source names a fixed version.