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CVE-2024-27443

81
FAUCET Score

CVE-2024-27443 is a Cross-Site Scripting (XSS) vulnerability in Zimbra Collaboration (ZCS) versions 9.0 and 10.0, specifically within the CalendarInvite feature of the classic webmail interface. This medium-severity vulnerability (CVSS 6.1) allows an unauthenticated attacker to execute arbitrary JavaScript by sending a specially crafted email with an embedded XSS payload in the calendar header, which triggers when a victim views the message. The vulnerability is actively exploited in the wild, as indicated by its presence in the KEV catalog and high EPSS score, and has garnered significant community discussion and media coverage. While no Metasploit or ExploitDB modules exist, Nuclei templates are available, suggesting readily accessible exploit code.

Impacted Technologies

VendorProductVersion(s)CPE
>= 10.0.0, < 10.0.7CPE matchmatch criteria
cpe:2.3:a:zimbra:collaboration:*:*:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:zimbra:collaboration:9.0.0:-:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:zimbra:collaboration:9.0.0:p0:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:zimbra:collaboration:9.0.0:p1:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:zimbra:collaboration:9.0.0:p10:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.1MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
2.7
CvssVersion
3.1

Exploit Intelligence

EPSS Score
23.63%
Probability of exploitation in next 30 days
EPSS Percentile
97.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Added to KEV · May 19, 2025
Nuclei: CVE-2024-27443 · Oct 9, 2025
This CVE's current EPSS score of 0.2363 is in the 99th percentile among its peer group of 26,234 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

cisa.gov / known-exploited-vulnerabilities-catalog
US Government Resource
welivesecurity.com / en/eset-research/operation-roundpress
Press/Media Coverage
wiki.zimbra.com / wiki/Zimbra_Releases/10.0.7
Release Notes
wiki.zimbra.com / wiki/Zimbra_Releases/9.0.0/P39
Release Notes