CVE-2026-93638 json
Zimbra Collaboration Suite Pre-Authentication Reflected Cross-Site Scripting via Login Page zrememberme Parameter
published 2026-10-23 17 d ago modified 2026-10-28 11 d ago also EUVD-2026-108977
- cvss
- 6.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 22%
- public exploits
- 0
- none known
Summary
A reflected cross-site scripting vulnerability in the login page of Zimbra Collaboration Suite (ZCS) allows an unauthenticated attacker to execute JavaScript through the zrememberme parameter. A crafted relogin URL selects a two-factor error display that inserts the parameter into a hidden input attribute without HTML encoding. A victim who opens the URL receives attacker-controlled script and page content under the legitimate Zimbra origin, allowing credential capture through a replacement login form. The relogin path logs out an existing session before rendering the payload, so the demonstrated attack does not inherit that session's mailbox access. ZCS 10.1.16 and 10.1.17 are affected.
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 11 d ago
Exploit prediction
0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- rapid7.com https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected products
- Zimbra Zimbra Collaboration Suite
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
rapid7.com
/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/
related, exploit, third-party-advisory
-
wiki.zimbra.com
/wiki/Zimbra_Security_Advisories
vendor-advisory
Sources
- CVE List CVE-2026-93638
- NVD CVE-2026-93638
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