CVE-2024-27443Known exploitationPublic exploitNetwork attack vector

Session script execution via unsanitized calendar header

Published Aug 12, 2024 · Updated Oct 21, 2025

Stored XSS in Zimbra Collaboration 9.0 and 10.0 allows remote attackers to execute JavaScript by sending a crafted calendar invite. ZmInviteMsgView.js inserts the cif value from X-Zimbra-Calendar-Intended-For directly into the Classic UI page without sanitization. Execution requires a victim to open the email in the Classic UI and exposes data and actions available to that webmail session.

CVSS severity6.1
Medium
EPSS probability23.63%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Zimbra Collaboration 9.0 and 10.0 allows remote attackers to execute JavaScript by sending a crafted calendar invite. ZmInviteMsgView.js inserts the cif value from X-Zimbra-Calendar-Intended-For directly into the Classic UI page without sanitization. Execution requires a victim to open the email in the Classic UI and exposes data and actions available to that webmail session.

The record

CVE
CVE-2024-27443
Published
Aug 12, 2024
Updated
Oct 21, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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