Page generated: 11 Nov 2026, 11:43 UTC
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CVE-2024-27443

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 attack…

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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.
CVSS 6.1 (MEDIUM) KEV: KNOWN CATALOG

Attention and evidence

HYPE SCORE
0.0/10
REALITY · THREAT PRIORITY
8.0/10
General review priority; not probability

Evidence confidence: Exploitation recorded

Why this priority?
  • Recorded exploitation baseline: +7.00
  • Technical severity: CVSS 6.1: +0.91
  • Fresh EPSS: 24.61%: +0.12

General review priority, not probability, victim count or asset-specific risk. A range covers missing CVSS/EPSS inputs within the current evidence state.

Sources: 7 documents and public datasets.

Hype components

Headline sample (25%)
0/100
Press, 30 days (60%)
0/100
Grounded branding (15%)
0/100
HYPE TOTAL0/100

Sources and documents

The Hacker News
Press · 11 Jul 2026, 07:00 · Critical Zimbra Flaw Could Let Crafted Emails Run Malicious Code in User Sessions - The Hacker News
Security Affairs
Press · 10 Oct 2025, 07:00 · Ukraine sees surge in AI-Powered cyberattacks by Russia-linked Threat Actors - Security Affairs
The Hacker News
Press · 09 Oct 2025, 07:00 · From Phishing to Malware: AI Becomes Russia's New Cyber Weapon in War on Ukraine - The Hacker News
Dark Reading
Press · 19 May 2025, 07:00 · 'Operation RoundPress' Targets Ukraine Webmail Servers - Dark Reading
BleepingComputer
Press · 15 May 2025, 07:00 · Government webmail hacked via XSS bugs in global spy campaign - BleepingComputer
See all 7 source documents
The Hacker News
Press · 15 May 2025, 07:00 · Russia-Linked APT28 Exploited MDaemon Zero-Day to Hack Government Webmail Servers - The Hacker News
WeLiveSecurity
Press · 15 May 2025, 07:00 · Operation RoundPress targeting high-value webmail servers - WeLiveSecurity

Score evolution

● Hype   ● Reality

Earlier evidence-support scores are retained in history; this chart shows only the current priority definition.

First record: hype 0.0 · reality 8.0 (2026-11-02 15:13). The curve appears once the score changes.

Public exploit evidence

0

Public exploit entries / repo candidates

Evidence context and dated references

Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs.

Evidence in context

Confidence in exploitation evidence
Exploitation recorded
Priority basis
Recorded exploitation; CVSS 6.1; EPSS 24.6%
Attention, last 30 days
0 distinct story titles; 0 press documents; 0 publisher domains.
Technical potential
network access, no prior privileges, user interaction.
Observed activity
Exploitation recorded in CISA KEV.
Known scale
Not quantified.
Evidence confidence basis
Trusted exploitation confirmation

Score evaluated: 2026-11-05 13:59:10.297797+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z

Source event timeline
Published
12 Aug 2024, 00:00
First press mention
15 May 2025, 07:00
Added to the CISA KEV catalog
19 May 2025, 00:00
Latest press mention
11 Jul 2026, 07:00
Score calculated
05 Nov 2026, 13:59