CVE-2021-28994

Name: CVE-2021-28994
Creator: NVD / NIST
Published: 2021-03-31T23:15:11.767+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.05%

Last modified Jun 17, 2026

CVE-2021-28994 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. kopano-ical (formerly zarafa-ical) in Kopano Groupware Core through 8.7.16, 9.x through 9.1.0, 10.x through 10.0.7, and 11.x through 11.0.1 and Zarafa 6.30.x through 7.2.x allows memory exhaustion via long HTTP headers.. EPSS estimates a 2.05% chance of exploitation in the next 30 days.

Description

kopano-ical (formerly zarafa-ical) in Kopano Groupware Core through 8.7.16, 9.x through 9.1.0, 10.x through 10.0.7, and 11.x through 11.0.1 and Zarafa 6.30.x through 7.2.x allows memory exhaustion via long HTTP headers.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

2.05%

78.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-770

Affected Software

Vendor	Product	Versions
Kopano	Groupware Core	<= 8.7.16
Kopano	Groupware Core	>= 9.0.0, <= 9.1.0
Kopano	Groupware Core	>= 10.0.0, <= 10.0.7
Kopano	Groupware Core	>= 11.0.0, <= 11.0.1
Zarafa	Zarafa	>= 6.30.0, <= 7.2.6

References

http://www.openwall.com/lists/oss-security/2021/04/01/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/04/25/1Mailing List, Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/03/19/6Exploit, Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/04/01/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/04/25/1Mailing List, Third Party Advisory
https://www.openwall.com/lists/oss-security/2021/03/19/6Exploit, Mailing List, Third Party Advisory

Timeline

Published: Mar 31, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-28994?

How severe is CVE-2021-28994?

CVE-2021-28994 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.05% probability of exploitation in the next 30 days.

How do I fix CVE-2021-28994?

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-2021-28994?

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

Scan your code now

Source: NVD / NIST