Patch first › Zimbra (Synacor)
CVE-2022-37042
Zimbra (Synacor) Collaboration Suite (ZCS) · Email
Synacor Zimbra Collaboration Suite (ZCS) Authentication Bypass Vulnerability
At a glance
Exploited. Added to CISA’s catalog of exploited vulnerabilities on August 11, 2022.
Used in ransomware attacks, according to CISA.
Affected product: Zimbra (Synacor) Collaboration Suite (ZCS) (category Email, indicative classification). Name in CISA’s catalog: Synacor Zimbra Collaboration Suite (ZCS).
What should I do?
Apply the security update from Zimbra (Synacor).
Deadline set by CISA for US federal agencies: 21 days (due September 1, 2022). It only binds those agencies, but it is a useful measure of urgency.
- Zimbra (Synacor) security advisories page (general page, not the advisory for this vulnerability)
- The vendor’s specific advisory is listed in the NVD references: CVE-2022-37042 on the NVD website.
Original text of the required action (CISA)
Apply updates per vendor instructions.
Timeline
- Exploitation confirmed Added to CISA’s KEV catalog
- Vulnerability published Publication date (NVD)
- CISA deadline Remediation deadline set for US federal agencies
The facts, with their sources
- Exploitation confirmed
- Yes, on August 11, 2022 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Ransomware
- Known use Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Hunt for compromise
- Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CISA required action
- Apply the security update from Zimbra (Synacor). Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CISA deadline
- September 1, 2022, 21 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Vulnerability published
- August 12, 2022 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
- Product according to CISA
- Synacor Zimbra Collaboration Suite (ZCS) Filed by this site under “Email” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Severity and activity
FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.
Description
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.
Official description from the NVD, collected Sep 29, 2026. CVE® description © The MITRE Corporation.
Synacor Zimbra Collaboration Suite (ZCS) contains an authentication bypass vulnerability in MailboxImportServlet. This vulnerability was chained with CVE-2022-27925 which allows for unauthenticated remote code execution.
Summary from CISA (KEV catalog).
CERT-FR advisories
No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.
Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.
Sources for this page
- CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
- NVD (NIST): CVSS severity, publication date, description, vendor references.
- EPSS (FIRST): probability of exploitation.
- CERT-FR: advisories and alerts (in French).
- Brand and category: indicative classification by this site (method).