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PatchSiren cyber security CVE debrief

CVE-2026-93635 Zimbra CVE debrief

A vulnerability in Zimbra Collaboration Suite allows unauthenticated attackers to inject LDAP filter input, potentially creating a password oracle for external directory users. This issue affects Zimbra Collaboration Suite versions 10.1.0 through 10.1.21. The vulnerability can be exploited by injecting malicious LDAP filter input, which can lead to unauthorized access to sensitive information. Defenders should prioritize verifying and patching affected Zimbra Collaboration Suite instances, especially those using search-filter authentication and lazy provisioning.

Vendor
Zimbra
Product
Zimbra Collaboration Suite
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-14
Original CVE updated
2026-10-16
Advisory published
2026-10-14
Advisory updated
2026-10-16

Who should care

Defenders responsible for Zimbra Collaboration Suite instances, especially those using search-filter authentication and lazy provisioning, should assess exposure and prioritize patching.

Why it matters

Defenders should prioritize verifying and patching affected Zimbra Collaboration Suite instances, especially those using search-filter authentication and lazy provisioning, as this vulnerability allows unauthenticated attackers to inject LDAP filter input.

  • Potential creation of a password oracle for external directory users
  • Unauthenticated attackers can alter external LDAP search filters
  • Authenticated S/MIME lookups can return certificates and identity data for unintended directory entries

Technical summary

The vulnerability allows unauthenticated attackers to inject LDAP filter input, potentially creating a password oracle for external directory users. This issue affects Zimbra Collaboration Suite versions 10.1.0 through 10.1.21. The vulnerability is caused by the lack of proper input validation in the computeDn() function, which allows attackers to inject malicious LDAP filter input. This can lead to unauthorized access to sensitive information and potentially allow attackers to alter external LDAP search filters. Authenticated S/MIME lookups can also return certificates and identity data for unintended directory entries.

Defensive priority

Defenders should prioritize verifying and patching affected Zimbra Collaboration Suite instances, especially those using search-filter authentication and lazy provisioning.

Recommended defensive actions

  • Verify and patch affected Zimbra Collaboration Suite instances
  • Review authentication and provisioning configurations
  • Monitor for potential exploitation attempts
  • Perform vulnerability scanning to identify exposed instances
  • Implement compensating controls for exposed systems
  • Review asset inventory to ensure all instances are accounted for
  • Track exceptions and retest remediated assets

Evidence notes

The CVE record and source item provide details on the vulnerability, its impact, and affected versions. However, additional information from official sources may be necessary to fully assess the vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-93635 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-93635

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-93635 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-93635

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.