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VulnerabilityPublished

CVE-2026-93641: Zimbra Collaboration Suite (ZCS) · Cross-site Scripting

Affects Zimbra Collaboration Suite (ZCS)Source CVE Database V5

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Not known to be exploited · CVSS 9.3 Critical : upgrade to 10.1.21 as a priority.

Data as of 8 Nov 2026, 23:24 UTC

CVSS 3.1 base score
9.3Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 10.1.21
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

What to do

Upgrade Zimbra Collaboration Suite (ZCS) to 10.1.21.

Affected software

ProductAffectedFixed in
ZimbraZimbra Collaboration Suite (ZCS)Affected
  • <10.1.21
Fixed in
  • 10.1.21

AI-suggested

If you cannot patch yet, users should exercise caution when accepting share notifications from untrusted sources.

Description

CVE-2026-93641 is a critical stored cross-site scripting (XSS) vulnerability in Zimbra Collaboration Suite (ZCS) versions before 10.1.21. An unauthenticated attacker can send a forged share notification that triggers XSS when a signed-in Zimbra Classic user clicks Accept Share. This allows the attacker to access mailbox data and act on behalf of the victim.

References

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