Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-28994

21
FAUCET Score

CVE-2021-28994 is a memory exhaustion vulnerability affecting Kopano Groupware Core (versions 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 (versions 6.30.x through 7.2.x). This flaw allows an unauthenticated attacker to trigger a denial-of-service by sending specially crafted, long HTTP headers. Rated with a CVSS score of 7.5 (High), this vulnerability is easily exploitable over the network with low attack complexity, leading to high availability impact. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 8.7.16CPE matchmatch criteria
cpe:2.3:a:kopano:groupware_core:*:*:*:*:*:*:*:*
>= 9.0.0, <= 9.1.0CPE matchmatch criteria
cpe:2.3:a:kopano:groupware_core:*:*:*:*:*:*:*:*
>= 10.0.0, <= 10.0.7CPE matchmatch criteria
cpe:2.3:a:kopano:groupware_core:*:*:*:*:*:*:*:*
>= 11.0.0, <= 11.0.1CPE matchmatch criteria
cpe:2.3:a:kopano:groupware_core:*:*:*:*:*:*:*:*
>= 6.30.0, <= 7.2.6CPE matchmatch criteria
cpe:2.3:a:zarafa:zarafa:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.05%
Probability of exploitation in next 30 days
EPSS Percentile
79.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0205 is in the 63rd percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

openwall.com / lists/oss-security/2021/03/19/6
ExploitMailing ListThird Party Advisory
openwall.com / lists/oss-security/2021/04/01/1
Mailing ListThird Party Advisory
openwall.com / lists/oss-security/2021/04/25/1
Mailing ListThird Party Advisory