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CVE-2016-3415 Synacor CVE debrief

CVE-2016-3415 is a critical deserialization flaw affecting Zimbra Collaboration before 8.7.0. According to the supplied NVD record, remote attackers could trigger deserialization attacks via unspecified vectors, and the issue is tracked as bug 102276. The vulnerability is rated 9.1/CRITICAL, with network reachability and no privileges or user interaction required.

Vendor
Synacor
Product
CVE-2016-3415
CVSS
CRITICAL 9.1
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-18
Original CVE updated
2026-05-13
Advisory published
2017-01-18
Advisory updated
2026-05-13

Who should care

Organizations running Zimbra Collaboration 8.6.0 or earlier, especially internet-facing mail and collaboration deployments, should prioritize this issue. Security teams responsible for email infrastructure, identity-adjacent services, and legacy application platforms should verify patch status and upgrade path promptly.

Technical summary

The supplied NVD data classifies CVE-2016-3415 as CWE-502 (Deserialization of Untrusted Data). The vulnerable product scope is Zimbra Collaboration up to and including 8.6.0, with remediation indicated by the vendor release notes for 8.7.0. NVD assigns CVSS v3.0 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N, reflecting remote, low-complexity exploitation with high confidentiality and integrity impact.

Defensive priority

High. This is a remotely reachable, critical-severity deserialization issue with no privileges or user interaction required per the NVD vector. If Zimbra Collaboration is exposed or broadly accessible, treat patching and version verification as urgent.

Recommended defensive actions

  • Confirm whether any Zimbra Collaboration systems are running 8.6.0 or earlier.
  • Upgrade affected systems to a fixed version referenced by the vendor release notes for Zimbra 8.7.0 or later.
  • Review exposed mail and collaboration services for compensating controls such as network segmentation and restricted access.
  • Inventory all Zimbra instances, including test, backup, and forgotten edge deployments, to avoid missing vulnerable hosts.
  • Monitor vendor advisories and internal change records for confirmation that the fix was applied successfully.

Evidence notes

All statements are derived from the supplied NVD record and the referenced Zimbra release/advisory pages. The NVD record lists CVE-2016-3415 as a deserialization vulnerability (CWE-502) affecting Zimbra Collaboration through version 8.6.0, with CVSS 3.0 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. The description states the vector details are unspecified and cites bug 102276. The source corpus does not include additional exploit details, so no further attack mechanics are asserted here.

Official resources

CVE published by NVD on 2017-01-18 and last modified on 2026-05-13 in the supplied record. Vendor references point to Zimbra 8.7.0 release notes and Zimbra security advisories; no exploit code or offensive reproduction details are included.