How severe is CVE-2016-3403?

CVE-2016-3403 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2016-3403 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-3403?

CVE-2016-3403 affects Synacor Zimbra Collaboration Suite. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-3403?

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

When was CVE-2016-3403 published?

CVE-2016-3403 was published on 2017-05-17 and last updated on 2026-06-17.

CVE-2016-3403

CVE-2016-3403 is a high-severity vulnerability in Synacor Zimbra Collaboration Suite with a CVSS 3.x base score of 8.8. 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-352.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-352
Affected product: Synacor Zimbra Collaboration Suite
Published: 2017-05-17
Last modified: 2026-06-17

Description

Multiple cross-site request forgery (CSRF) vulnerabilities in the Admin Console in Zimbra Collaboration before 8.6.0 Patch 8 allow remote attackers to hijack the authentication of administrators for requests that (1) add, (2) modify, or (3) remove accounts by leveraging failure to use of a CSRF token and perform referer header checks, aka bugs 100885 and 100899.

Frequently asked questions

What is CVE-2016-3403?: Multiple cross-site request forgery (CSRF) vulnerabilities in the Admin Console in Zimbra Collaboration before 8.6.0 Patch 8 allow remote attackers to hijack the authentication of administrators for requests that (1) add, (2) modify, or (3) remove accounts by leveraging failure to use of a CSRF token and perform referer header checks, aka bugs 100885 and 100899.
How severe is CVE-2016-3403?: CVE-2016-3403 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-3403 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-3403?: CVE-2016-3403 affects Synacor Zimbra Collaboration Suite. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-3403?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2016-3403 published?: CVE-2016-3403 was published on 2017-05-17 and last updated on 2026-06-17.

References

Affected products (1)

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

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