An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0.
Affects Zimbra Collaboration 9.0 and 10.0 through a Calendar invite. The listed fix is the Daffodil 10.0.7 patch release for the 10.0 line.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Actively exploited
- Fix
- Fixed in 10.0.7
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Zimbra Collaboration (ZCS) 9.0 and 10.0 webmail classic interface is affected. A crafted calendar invite email can run malicious JavaScript in a victim's browser session when they view it, potentially allowing attacker-controlled actions within their account.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
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.
Timeline
- CVE published
- Added to CISA KEV
CISA has evidence of exploitation in the wild
- CISA remediation deadline
Due date for US federal agencies to patch
- Record last updated
- EPSS reached 10%
FIRST estimates at least a 10% chance of exploitation in the next 30 days
Affected versions
- n/a n/a
Version range not reported
References 2
Questions about CVE-2024-27443
What does this mean?
This is a cross-site scripting (XSS) flaw in the Calendar invite feature. Script can run in the browser of a user who views the affected invite.Source: wiki.zimbra.com
Am I affected, and how do I check?
The advisory names Zimbra Collaboration (ZCS) 9.0 and 10.0. Check which Zimbra Collaboration version is installed to see which release line applies.Source: wiki.zimbra.com
What should I do about it?
Upgrade to Zimbra Collaboration Daffodil 10.0.7, the patch release the advisory lists as the fix.Source: wiki.zimbra.com
Is it being exploited?
Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-05-19, which means it has evidence of attacks. No public exploit code is tracked.Source: cisa.gov, cve.now feed data