Security readout for executives and security teams
Plain-English summary
This flaw is a stored cross-site scripting issue in Zimbra Collaboration Suite mailboxd. If exploitable in an organization’s Zimbra environment, malicious content could persist and run in a user’s browser when viewed, creating account and mail-system risk. The public bundle does not provide CVSS details or confirmed exploitation.
Executive priority
Prioritize remediation if Zimbra is internet-facing or used for sensitive mail. This is not KEV-listed in the supplied bundle, but stored XSS in a collaboration platform can expose users, sessions, and trusted internal workflows.
Technical view
CVE-2018-18631 affects Synacor Zimbra Collaboration Suite 8.6, 8.7 before 8.7.11 Patch 7, and 8.8 before 8.8.10 Patch 2. The vulnerable component is mailboxd, and the issue is described as Persistent XSS. No CWE, CVSS vector, or exploit details are provided in the bundle.
Likely exposure
Exposure is most likely in organizations running Zimbra Collaboration Suite 8.6, 8.7 earlier than 8.7.11 Patch 7, or 8.8 earlier than 8.8.10 Patch 2, especially internet-accessible mail services.
Exploitation context
The source bundle does not show CISA KEV listing or any cited evidence of active exploitation. Treat exploitation status as unconfirmed. Persistent XSS generally requires malicious content to be stored and later viewed by another user, but source details are limited.
Researcher notes
Public details are sparse: the bundle identifies affected Zimbra versions, mailboxd, and Persistent XSS, but not root cause, CVSS, CWE, exploit prerequisites, or specific patched code. Avoid assuming exploitability beyond the stated affected ranges.
Mitigation direction
- Inventory all Zimbra Collaboration Suite deployments and patch levels.
- Upgrade 8.7 deployments to 8.7.11 Patch 7 or later.
- Upgrade 8.8 deployments to 8.8.10 Patch 2 or later.
- For 8.6 deployments, check Zimbra guidance for supported upgrade paths.
- Restrict administrative access and monitor exposed Zimbra services.
Validation and detection
- Confirm whether mailboxd is present on each Zimbra deployment.
- Compare installed Zimbra versions against the affected ranges.
- Review Zimbra security advisories and Bugzilla entry 109020.
- After remediation, verify systems report patched or later versions.
- Check mail-system logs for suspicious stored-content or account activity.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2018-18631 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://wiki.zimbra.com/wiki/Zimbra_Security_AdvisoriesCVE reference · x_refsource_MISC
- https://bugzilla.zimbra.com/show_bug.cgi?id=109020CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.