CVE-2024-27443
Confirmed PUBLISHEDAn issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. A Cross-Site Scripting (XSS) vulnerability exists in the CalendarInvite feature...
377 days faster than CISA KEV
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. A Cross-Site Scripting (XSS) vulnerability exists in the CalendarInvite feature of the Zimbra webmail classic user interface, because of improper input validation in the handling of the calendar header. An attacker can exploit this via an email message containing a crafted calendar header with an embedded XSS payload. When a victim views this message in the Zimbra webmail classic interface, the payload is executed in the context of the victim's session, potentially leading to execution of arbitrary JavaScript code.
- CVE Published
- Aug 12, 2024
- Exploitation Reported
- May 21, 2025
- CVSS
- 6.1 Medium
- EPSS
- 19.5%
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| n/a |
n/a
|
n/a |
Affected |
CVE References
- wiki.zimbra.com/wiki/Zimbra_Releases/10.0.7 wiki.zimbra.com · CVE Record https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.7#Security_Fixes
- wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P39 wiki.zimbra.com · CVE Record https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P39#Security_Fixes
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CVE First | 2025-05-21 13:10 UTC |
| CISA | 2026-06-02 14:07 UTC |
Scanner Artifacts
Nuclei and Metasploit references linked to this CVE.
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2024/CVE-2024-27443.yaml | Jun 01, 2026 |
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Exploitation Status
Exploited in the wild
Recorded 2025-05-21 13:10:39 UTC · CVE
Proof of concept available
Recorded 2026-06-12 14:21:02 UTC · Nuclei Templates
Weaknesses (CWE)
-
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Scanner Integrations
| Scanner | Reference | Detected |
|---|---|---|
| Nuclei | https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2024/CVE-2024-27443.yaml | Jun 01, 2026 |
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
nuclei · Created Unknown
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
14:21 UTC about 1 month ago14:21 UTC · about 1 month ago
Public PoC available
Public proof-of-concept code published
-
14:07 UTC about 2 months ago14:07 UTC · about 2 months ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
15:34 UTC about 2 months ago15:34 UTC · about 2 months ago
Nuclei template available
Scanner coverage available
-
13:10 UTC about 1 year ago13:10 UTC · about 1 year ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
00:00 UTC almost 2 years ago00:00 UTC · almost 2 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC over 2 years ago00:00 UTC · over 2 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2024-27443
{
"cve_id": "CVE-2024-27443",
"title": "An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. A Cross-S...",
"affected_vendor": "Zimbra",
"affected_product": "Zimbra Collaboration (ZCS)",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 6.1,
"epss_score": 0.19543,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}