CVE-2021-28994

HIGHNVD 7.57.5—

7.5

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.

CVSS v3: 7.5
EG Score: 7.5(medium)
EPSS: 61.5%
KEV: Not listed

Published

March 31, 2021

Last Modified

November 21, 2024

References (6)

cve@mitrehttp://www.openwall.com/lists/oss-security/2021/04/01/1
cve@mitrehttp://www.openwall.com/lists/oss-security/2021/04/25/1
cve@mitrehttps://www.openwall.com/lists/oss-security/2021/03/19/6
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2021/04/01/1
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2021/04/25/1
af854a3a-2127-422b-91ae-364da2661108https://www.openwall.com/lists/oss-security/2021/03/19/6

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 18× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 18:58 UTCEG score recompute
2026-05-26 18:58 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-28994?

CVE-2021-28994 is a high vulnerability published on March 31, 2021. 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.

When was CVE-2021-28994 disclosed?

CVE-2021-28994 was first published in the National Vulnerability Database on March 31, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-28994 actively exploited?

CVE-2021-28994 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 61.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-28994?

CVE-2021-28994 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2021-28994?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-28994, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-28994

📅 Published

🔄 Last Modified

🔗 References (6)

Weakness Classification(2)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-28994?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (6)

Frequently asked(5)

Related CVEs(same CWE)