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Weekly Signal
Live intelligence Updated 20 Aug 2026 · 01:51 UTC

Synacor · Zimbra Collaboration Suite, Zimbra Collaboration Suite (ZCS)

CVE-2022-37042

Synacor Zimbra Collaboration Suite (ZCS) Authentication Bypass Vulnerability

Recommended action

Treat this as an immediate remediation priority. Apply updates per vendor instructions.

View response plan
CVSS9.8
EPSS91.9%
KEVYes
ExploitationConfirmed exploitation
PatchPatch or guidance available ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 91.9%; technical severity is CVSS 9.8.

Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0 has mboximport functionality that receives a ZIP archive and extracts files from it. By bypassing authentication (i.e., not having an authtoken), an attacker can upload arbitrary files to the system, leading to directory traversal and remote code execution. NOTE: this issue exists because of an incomplete fix for CVE-2022-27925.

Who should care

  • Teams operating Zimbra Collaboration Suite, Zimbra Collaboration Suite (ZCS)
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether Zimbra Collaboration Suite, Zimbra Collaboration Suite (ZCS) is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Apply updates per vendor instructions.
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Vendor remediation

Patch and remediation links

Use the vendor source below to confirm the correct fixed version, package or mitigation for your affected product.

Technical details

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-23
Affected versions
Synacor Zimbra Collaboration Suite (Version: 9.0.0); Synacor Zimbra Collaboration Suite (ZCS)
Published
12 August 2022
Attack vector
Network
Privileges required
None
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 91.9%
  4. Signal calculated at 87

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.