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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 25 Aug 2022. Known ransomware use
Zimbra Collaboration SuiteApplication · Synacor

CVE-2022-27924

HIGH · 7.5 CVSS v3.1 Published 2022-04-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware High EPSS Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Zimbra Collaboration (aka ZCS) 8.8.15 and 9.0 allows an unauthenticated attacker to inject arbitrary memcache commands into a targeted instance. These memcache commands becomes unescaped, causing an overwrite of arbitrary cached entries.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Zimbra Collaboration Suite 8.8.15 and 9.0 contains an unauthenticated memcache command injection vulnerability. Attackers can inject arbitrary memcache commands without authentication, and these commands are not properly escaped, allowing overwrite of arbitrary cached entries in the memcache instance.

MitigationApply vendor-supplied patches for CVE-2022-27924 and restrict network exposure of memcache services to prevent unauthenticated attackers from reaching the vulnerable memcache interface.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Zimbra Collaboration SuiteApplication
Affected:= 8.8.15= 9.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed Zimbra version
    Run 'zmcontrol -v' or check '/opt/zimbra/.install_history' to identify the exact Zimbra Collaboration Suite version installed
    Affected if Version is 8.8.15 or 9.0.0 (any patch level)
  2. Confirm memcached is in use
    Check if the Zimbra memcached service is running: 'ps aux | grep memcached' or check Zimbra configuration for memcached proxy settings
    Affected if Memcached is running as part of Zimbra infrastructure and serves as a caching layer for the collaboration suite
  3. Verify memcached network exposure
    Check memcached bind address in configuration files (typically in /opt/zimbra/conf/memcached.conf or via 'netstat -tlnp | grep 11211')
    Affected if Memcached is bound to 0.0.0.0 or an externally accessible IP address rather than localhost only (127.0.0.1)
  4. Check memcached authentication status
    Review memcached configuration for SASL or other authentication enforcement; attempt a simple telnet connection to port 11211 to see if unauthenticated commands are accepted
    Affected if No authentication is required to send commands to the memcached service

A user is affected if they run Zimbra 8.8.15 or 9.0.0 with memcached exposed on the network without authentication controls in place.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-supplied patches for CVE-2022-27924 and restrict network exposure of memcache services to prevent unauthenticated attackers from reaching the vulnerable memcache interface.

Recommended fix High confidence

Zimbra 8.8.15 Patch 18+ or Zimbra 9.0.0 Patch 11+ (or latest 9.0.0z stable release)

  1. 1. Back up your current Zimbra configuration and mail data before starting any upgrade process.
  2. 2. Identify your current Zimbra version by running: zmcontrol -v
  3. 3. For Zimbra 8.8.15: Upgrade to version 8.8.15 Patch 18 or later, which contains the fix for CVE-2022-27924.
  4. 4. For Zimbra 9.0.0: Upgrade to version 9.0.0 Patch 11 or later, which contains the fix for CVE-2022-27924.
  5. 5. Alternatively, upgrade to the latest stable Zimbra 9.0.0z release for the most current security patches.
  6. 6. After upgrade, verify the memcache service is running correctly and test that cached data behaves as expected.
  7. 7. Monitor Zimbra logs for any suspicious memcache activity to confirm the vulnerability is mitigated.
Caveat Review Zimbra release notes for your target version to check for any breaking changes or deprecated features between your current version and the upgrade target

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Zimbra Collaboration Suite Exploited in the wild — priority engagement
  • Consultation6.0 h
  • Implementation10.0 h
  • Testing6.0 h
  • Review / QA4.0 h
26.0 hours of engineering $4,620
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-27924 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data