CVE-2021-36580

MEDIUMNVD 6.16.1—Elevated

6.1

Open Redirect vulnerability exists in IceWarp MailServer IceWarp Server Deep Castle 2 Update 1 (13.0.1.2) via the referer parameter.

CVSS v3: 6.1
EG Score: 6.1(medium)
EPSS: 93.2%
KEV: Not listed

Published

July 27, 2023

Last Modified

November 21, 2024

References (6)

cve@mitrehttp://icewarp.com
cve@mitrehttp://mail.ziyan.com
cve@mitrehttps://medium.com/%40rohitgautam26/cve-2021-36580-69219798231c
af854a3a-2127-422b-91ae-364da2661108http://icewarp.com
af854a3a-2127-422b-91ae-364da2661108http://mail.ziyan.com
af854a3a-2127-422b-91ae-364da2661108https://medium.com/%40rohitgautam26/cve-2021-36580-69219798231c

Weakness Classification(1)

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

CWE-601URL Redirection to Untrusted Site (Open Redirect)

Data Freshness Timeline

(refreshed 10× in last 7d / 15× 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
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 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
2026-05-27 13:39 UTCepss_batch
2026-05-24 20:32 UTCEG score recompute
2026-05-24 20:32 UTCGHSA enrichment

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

Nucleihttp/cves/2021/CVE-2021-36580.yaml
First seen Jan 1, 2021
IceWarp Mail Server - Open Redirect
Open source ↗

Frequently asked(5)

What is CVE-2021-36580?

CVE-2021-36580 is a medium vulnerability published on July 27, 2023. Open Redirect vulnerability exists in IceWarp MailServer IceWarp Server Deep Castle 2 Update 1 (13.0.1.2) via the referer parameter.

When was CVE-2021-36580 disclosed?

CVE-2021-36580 was first published in the National Vulnerability Database on July 27, 2023, 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-2021-36580 actively exploited?

CVE-2021-36580 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 93.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-36580?

CVE-2021-36580 has a CVSS v3 base score of 6.1 (NVD).

How do I remediate CVE-2021-36580?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-36580, 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-2021-36580

📅 Published

🔄 Last Modified

🔗 References (6)

Weakness Classification(1)

Data Freshness Timeline

Publicly available exploits

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-36580?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (6)

Frequently asked(5)

Related CVEs(same CWE)