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TI-2026-79912 Aliases CVE-2026-93631GHSA-8c8x-hffr-47hm

Cross-site request forgery in Zimbra OAuth extension links accounts

Priority LOW 30CWE-352Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Tampering
Confidentiality · integrity · availability
High · Low · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-352.

Summary

Zimbra Collaboration Suite (ZCS) Network Edition 10.1.16 and 10.1.20 are affected. The OAuth callback does not bind its state value or authorization code to the initiating session, so it links the mailbox selected by the browser's authentication cookie (CWE-352). An attacker who induces a signed-in victim to load a crafted callback can link an external account they control to the victim's mailbox, which then imports attacker-controlled contacts or events; with bidirectional CalDAV synchronization, appointments created or edited in the linked calendar are also disclosed to the attacker. A public exploit link appears in the references.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

A cross-site request forgery vulnerability in the OAuth extension of Zimbra Collaboration Suite (ZCS) Network Edition allows an attacker to link an attacker-controlled external account to a victim's mailbox. The OAuth callback does not bind its state value or authorization code to the initiating Zimbra session and instead selects the destination mailbox from the browser's current authentication cookie. On a deployment with the provider configured, an attacker can induce a signed-in victim to load a callback containing a fresh code for the attacker's provider account. This creates a persistent data source that imports attacker-controlled contacts or events. With bidirectional CalDAV synchronization, appointments subsequently created or edited in the linked calendar are also disclosed to the attacker. ZCS 10.1.16 and 10.1.20 are affected.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00175 7th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ZimbraZimbra Collaboration Suiteup to 10.1.20—No fix listedCNA
  • Zimbra Collaboration Suite VendorZimbra Affected up to 10.1.20 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*up to 10.1.20VulnerableSynacor
  • cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:* Versions up to 10.1.20 Vulnerable ·Synacor

Remediation

The sources list no fixed version for Zimbra Collaboration Suite.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Timeline

  1. 2026-10-23 Threatist record created from CVE-2026-93631
  2. 2026-10-23 Alias added: GHSA-8c8x-hffr-47hm
  3. 2026-10-24 Priority changed: MEDIUM → LOW
  4. 2026-10-28 CISA SSVC decision points changed

References

Exploit 1

Advisory 1

  • TI-2026-51660 OS command injection in Zimbra Collaboration KEVCVSS 3.1HIGH 8.9
  • TI-2025-40820 Cross-site scripting in Zimbra Collaboration KEVCVSS 3.1HIGH 7.2
  • TI-2024-18266 An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0. KEVCVSS 3.1MEDIUM 6.1
  • TI-2024-30553 An issue was discovered in Zimbra Collaboration (ZCS) 10.1.x before 10.1.1, 10.0.x before… CVSS 3.1HIGH 8.8
  • TI-2022-13998 Zimbra Collaboration Open Source 8.8.15 does not encrypt the initial-login randomly… CVSS 3.1CRITICAL 9.8
  • TI-2026-63080 Path traversal in Zimbra Collaboration Suite CVSS 3.1CRITICAL 9.8
See all 94 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences