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CVE-2026-93638

Zimbra Collaboration Suite Pre-Authentication Reflected Cross-Site Scripting via Login Page zrememberme Parameter

CVSS score

6.1

EPSS probability

—

Risk score

0.6

Published

2 h ago

Patch status has not yet been verified

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Vulnerability description

DayBreach AI Explanation

Verified against sources

Zimbra Collaboration Suite Pre-Authentication Reflected Cross-Site Scripting via Login Page zrememberme Parameter

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

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. Opening a crafted URL displays a replacement login form under the legitimate origin, enabling credential capture.

Why does it matter?

This flaw allows attackers to execute scripts under the legitimate Zimbra origin and capture user credentials through a replacement login form.

What should be done?

  • Follow vendor advisories
  • Monitor Zimbra security advisory updates
Chain of evidence and sources2 verified claims

Zimbra Collaboration Suite (ZCS) oturum açma sayfasındaki zrememberme parametresi, kimlik doğrulaması gerektirmeyen yansıtmalı siteler arası kod çalıştırma zafiyetine neden olur.

ZCS 10.1.16 ve 10.1.17 sürümleri bu zafiyetten etkilenmektedir.

Show the technical text from the sources

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.

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE: CWE-79

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-93638 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1ZimbraZimbra Collaboration Suite View
Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
6.1CVSS V3_1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NCVE CNA
6.1CVSS V31MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-93638 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-93638 weaknesses.

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekiyor

Official Sources and Advisories

CVSS Vector Radar Chart

6.1 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.RequiredConfidentialityLowIntegrityLowAvailabilityNone

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User Interaction—
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)Low
Availability (Erişilebilirlik)None

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

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Zimbra logo
Zimbra

Weakness Type (CWE & CAPEC)

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CVE-2026-93638 · Zimbra Collaboration Suite…