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VulnerabilityPublished

CVE-2026-93638: Zimbra Collaboration Suite · Cross-site Scripting

Affects Zimbra Collaboration SuiteSource CVE Database V5

0

Not known to be exploited · CVSS 6.1 Medium.

Data as of 26 Oct 2026, 14:00 UTC

CVSS 3.1 base score
6.1Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: 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 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
ZimbraZimbra Collaboration SuiteAffected
  • <=10.1.17
Fixed in–

AI-suggested

Until a fix is available, users should be cautious about opening unsolicited or suspicious relogin URLs.

Description

CVE-2026-93638 is a reflected cross-site scripting (XSS) vulnerability in the login page of Zimbra Collaboration Suite (ZCS) versions up to 10.1.17. It arises from improper neutralization of the zrememberme parameter, which is inserted into a hidden input attribute without HTML encoding during a two-factor error display. An unauthenticated attacker can craft a relogin URL that executes arbitrary JavaScript in the victim's browser under the legitimate Zimbra origin, potentially capturing credentials via a fake login form. The attack logs out any existing session before rendering, so mailbox access from the prior session is not inherited. The vulnerability has a CVSS score of 6.1 (medium severity).

References

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