CVE-2024-27443

criticalknown exploitedpublic exploitcovered by 1 sourcefirst seen 2025-05-19

Actively exploited. CVE-2024-27443 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-05-19) — exploitation has been observed in the wild, and US federal agencies are required to remediate it under BOD 22-01. Treat patching as urgent.

Public exploit code is available. Proof-of-concept or working exploit code for CVE-2024-27443 is indexed in Nuclei. Expect opportunistic scanning and exploitation attempts — prioritize remediation.

Zimbra Collaboration contains a cross-site scripting (XSS) vulnerability in the CalendarInvite feature of the Zimbra webmail classic user interface. An attacker can exploit this vulnerability via an email message containing a crafted calendar header, leading to the execution of arbitrary JavaScript code.

CSIRTS triage

What: There is a cross-site scripting (XSS) vulnerability in the CalendarInvite feature of the Zimbra webmail classic user interface.
Who is affected: Deployments of Zimbra Collaboration Suite that utilize the affected feature.
Urgency: Remediation is urgent due to active exploitation and critical severity.
Action: Apply the latest security patch provided by Zimbra.

AI-assisted analysis generated from the source advisory — verify against the original.

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Exploitation outlook

Exploitation confirmedAlready exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 97% of all EPSS-scored CVEs.

Exploit availability

Public exploit or proof-of-concept code for CVE-2024-27443 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.

NucleiA nuclei-templates detection/PoC template exists for this CVE.look it up ↗

Advisory coverage (1)

criticalexploitedCVE-2024-27443: Synacor Zimbra Collaboration Suite (ZCS) Cross-Site Scripting (XSS) Vulnerabilitycisa-kev · 2025-05-19

External references

NVD record for CVE-2024-27443

CVE.org record

CISA KEV catalog

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