How severe is CVE-2017-6821?

CVE-2017-6821 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-6821 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-6821?

CVE-2017-6821 affects Synacor Zimbra Collaboration Suite. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-6821?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2017-6821 published?

CVE-2017-6821 was published on 2017-05-23 and last updated on 2026-06-17.

CVE-2017-6821

CVE-2017-6821 is a critical-severity vulnerability in Synacor Zimbra Collaboration Suite with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Synacor Zimbra Collaboration Suite
Published: 2017-05-23
Last modified: 2026-06-17

Description

Directory traversal vulnerability in Zimbra Collaboration Suite (aka ZCS) before 8.7.6 allows attackers to have unspecified impact via unknown vectors.

Frequently asked questions

What is CVE-2017-6821?: Directory traversal vulnerability in Zimbra Collaboration Suite (aka ZCS) before 8.7.6 allows attackers to have unspecified impact via unknown vectors.
How severe is CVE-2017-6821?: CVE-2017-6821 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-6821 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-6821?: CVE-2017-6821 affects Synacor Zimbra Collaboration Suite. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-6821?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2017-6821 published?: CVE-2017-6821 was published on 2017-05-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*

More vulnerabilities in Synacor Zimbra Collaboration Suite

CVE-2024-45519 — Critical (CVSS 10.0): The postjournal service in Zimbra Collaboration (ZCS) before 8.8.15 Patch 46, 9 before 9.0.0 Patch 41, 10 before…
CVE-2022-41352 — Critical (CVSS 9.8): An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15 and 9.0. An attacker can upload arbitrary files through…
CVE-2022-37042 — Critical (CVSS 9.8): Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0 has mboximport functionality that receives a ZIP archive and extracts…
CVE-2020-7796 — Critical (CVSS 9.8): Zimbra Collaboration Suite (ZCS) before 8.8.15 Patch 7 allows SSRF when WebEx zimlet is installed and zimlet JSP is…
CVE-2019-9670 — Critical (CVSS 9.8): mailboxd component in Synacor Zimbra Collaboration Suite 8.7.x before 8.7.11p10 has an XML External Entity injection…
CVE-2019-6980 — Critical (CVSS 9.8): Synacor Zimbra Collaboration Suite 8.7.x through 8.8.11 allows insecure object deserialization in the IMAP component.

All CVEs affecting Synacor Zimbra Collaboration Suite →

Other CWE-22 (Path Traversal) vulnerabilities

CVE-2026-55393 — Critical (CVSS 10.0): Unvalidated pathnames in the web interface in Teledyne FLIR Aware2 versions through 6.9.0.2 (PackBot) and 1.7.9…
CVE-2026-97163 — Critical (CVSS 10.0): Joomla Extension - lomart.fr - Unauthenticated remote code installation in UP plugin extension 5.0.0-5.2.0, 6.0.0-6.0.29
CVE-2026-80155 — Critical (CVSS 10.0): Lantronix SLC8000 before firmware v9.7.0.5, SLC9000 before firmware v9.7.0.2, EMG8500/EMG7500 before firmware v9.7.0.1,…
CVE-2026-70200 — Critical (CVSS 10.0): Improper limitation of a pathname to a restricted directory ('path traversal') in Azure Logic Apps allows an…
CVE-2026-85706 — Critical (CVSS 10.0): GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.7 before 18.11.12, 19.0 before 19.0.9,…
CVE-2026-76606 — Critical (CVSS 10.0): Joomla Extension - fabrikar.com - Path Traversal via image element in Fabrik < 4.7.2.

Browse all CWE-22 (Path Traversal) vulnerabilities →