CVE-2021-28994

Exp

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.

Published: 2021-03-31 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-28994 is rated High Exploit Risk (74.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.05%). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.64% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-28994

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-28994

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.41% 2.05% +1.64%
2 2025-03-30 0.49% 0.41% -0.08%
3 2025-03-29 — 0.49% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-28994

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-28994

OS Trackers for CVE-2021-28994

vendor priority summary link
ubuntu medium CVE-2021-28994 medium priority: Ubuntu including 1 source packages (kopanocore), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 8, ignored 4, needed 3, released 1. https://ubuntu.com/security/CVE-2021-28994

Affected software / configurations for CVE-2021-28994

Vendor Product Version Raw CPE
kopano groupware_core <= 8.7.16 cpe:2.3:a:kopano:groupware_core:*:*:*:*:*:*:*:*
kopano groupware_core >= 9.0.0, <= 9.1.0 cpe:2.3:a:kopano:groupware_core:*:*:*:*:*:*:*:*
kopano groupware_core >= 10.0.0, <= 10.0.7 cpe:2.3:a:kopano:groupware_core:*:*:*:*:*:*:*:*
kopano groupware_core >= 11.0.0, <= 11.0.1 cpe:2.3:a:kopano:groupware_core:*:*:*:*:*:*:*:*
zarafa zarafa >= 6.30.0, <= 7.2.6 cpe:2.3:a:zarafa:zarafa:*:*:*:*:*:*:*:*

References for CVE-2021-28994

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