Security readout for executives and security teams
Plain-English summary
CVE-2024-27443 lets a malicious calendar email run JavaScript when viewed in Zimbra classic webmail. The issue requires user interaction, but CISA KEV and ESET reporting indicate real-world exploitation. Treat exposed Zimbra webmail as a priority, especially where classic UI is used.
Executive priority
Prioritize remediation above a typical medium CVSS XSS because trusted government and third-party sources indicate exploitation. The business risk is session-level compromise through routine email handling in Zimbra webmail.
Technical view
This is a CWE-79 XSS in Zimbra Collaboration 9.0 and 10.0 CalendarInvite handling. Improper validation of a calendar header allows embedded script execution in the victim's webmail session when the crafted message is viewed in the classic interface. CVSS is 6.1, but exploitation evidence raises operational risk.
Likely exposure
Organizations running Zimbra Collaboration 9.0 or 10.0 with users accessing the classic webmail interface are the relevant exposure group. The source bundle does not provide complete CPEs or exact vulnerable build ranges beyond those versions.
Exploitation context
CISA lists this CVE in KEV, and ESET's Operation RoundPress reporting is cited as third-party evidence. The attack path is email-delivered and user-triggered, so mailbox-facing users are the practical target surface. No exploit procedure is provided here.
Researcher notes
Key unknowns are exact vulnerable build boundaries and any vendor-supported workaround beyond the cited release security fixes. Validation should focus on ZCS version, classic UI usage, patch state, and evidence of crafted calendar-header messages.
Mitigation direction
- Review Zimbra 10.0.7 and 9.0.0 P39 security fixes for applicability.
- Apply the relevant vendor security update or current Zimbra guidance.
- Identify and reduce use of the classic webmail interface where feasible.
- Monitor mailboxes and webmail logs for suspicious calendar invite activity.
- Prioritize remediation for internet-facing or high-value Zimbra environments.
Validation and detection
- Inventory Zimbra Collaboration 9.0 and 10.0 deployments.
- Confirm whether users access the classic webmail interface.
- Check installed Zimbra patch levels against vendor security-fix pages.
- Review CISA KEV status for required remediation timelines.
- Search security telemetry for unusual calendar invite messages or webmail script indicators.
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.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2024-27443 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
- Medium
- CVSS
- 6.1 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.7#Security_FixesCVE reference
- https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P39#Security_FixesCVE reference
- https://www.welivesecurity.com/en/eset-research/operation-roundpress/CVE reference · third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-27443CVE reference · government-resource
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.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.