CVE-2020-8633Network attack vector

Revoked calendar access via stale Outlook mount

Published Feb 18, 2020 · Updated Aug 4, 2024

Improper permission revocation in Zimbra Collaboration Suite before 8.8.15 Patch 7 allows remote authenticated users to read revoked calendars. The Outlook Connector profile retains the mounted shared calendar instead of removing it when the grantor revokes the share. The flaw requires a previously granted calendar share and preserves read access for the former grantee after revocation.

CVSS severity5.3
Medium
EPSS probability1.07%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper permission revocation in Zimbra Collaboration Suite before 8.8.15 Patch 7 allows remote authenticated users to read revoked calendars. The Outlook Connector profile retains the mounted shared calendar instead of removing it when the grantor revokes the share. The flaw requires a previously granted calendar share and preserves read access for the former grantee after revocation.

The record

CVE
CVE-2020-8633
Published
Feb 18, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-281, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 18, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-281Improper Preservation of Permissions
T1213Data from Information Repositories

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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