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Fencer Vulns
medium 5.4

CVE-2021-35208 json

An issue was discovered in ZmMailMsgView.js in the Calendar Invite component in Zimbra Collaboration Suite 8.8.x before 8.8.15 Patch 23.

published 2021-07-02 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21852

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 70%
public exploits
0
none known

Summary

An issue was discovered in ZmMailMsgView.js in the Calendar Invite component in Zimbra Collaboration Suite 8.8.x before 8.8.15 Patch 23. An attacker could place HTML containing executable JavaScript inside element attributes. This markup becomes unescaped, causing arbitrary markup to be injected into the document.

Patch / fix

  • zimbra collaboration 8.8.15

Exploit prediction

1.27% chance of exploitation in the next 30 days, higher than 70% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • blog.sonarsource.com https://blog.sonarsource.com/zimbra-webmail-compromise-via-email referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.