What is CVE-2021-35207?

CVE-2021-35207 is a medium-severity vulnerability in Zimbra Collaboration, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-07-02.

How severe is CVE-2021-35207?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Zimbra Collaboration

CVE-2021-35207

An issue was discovered in Zimbra Collaboration Suite 8.8 before 8.8.15 Patch 23 and 9.0 before 9.0.0 Patch 16. An XSS vulnerability exists in the login component of Zimbra Web Client, in which an attacker can execute arbitrary JavaScript by adding executable JavaScript to the loginErrorCode parameter of the login url.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-07-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.033 (88.0th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 88th percentile — 88.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.033 · newest: 0.033 · change: 0.000

Affected products

Zimbra Collaboration — versions 8.8.15, 9.0.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

wiki.zimbra.com/wiki/Zimbra_Security_Advisories (Vendor Advisory)
wiki.zimbra.com/wiki/Security_Center (Release Notes, Vendor Advisory)
wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P16 (Vendor Advisory)
wiki.zimbra.com/wiki/Zimbra_Releases/8.8.15/P23 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-35207?: CVE-2021-35207 is a medium-severity vulnerability in Zimbra Collaboration, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-07-02.
How severe is CVE-2021-35207?: Medium severity. CVSS v3 base score is 6.1 out of 10.