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Full vulnerability report · 2022
CVE-2022-27924High confidence

Synacor Zimbra Collaboration Suite (ZCS) Command Injection Vulnerability

Synacor · Zimbra Collaboration Suite (ZCS)

7.5HighCVSS 3.1
Recommended action
Mitigate now

CISA confirms exploitation in the wild and lists 2022-08-25 as the remediation due date.

Mitigation available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 4 Aug 2022

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 93.91% for the current model date.

Compensating controls

  • Apply the linked authoritative mitigation while planning the permanent fix.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Synacor Zimbra Collaboration Suite (ZCS) and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2022-32412

CISA KEV mirrored by ENISA

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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 4 Aug 2022. Evidence sources: cisa_kev.
ENISA score
9.8 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionMitigate now

CISA confirms exploitation in the wild and lists 2022-08-25 as the remediation due date.

Mitigation available
01

What, why and how

Synacor Zimbra Collaboration Suite (ZCS) allows an attacker to inject memcache commands into a targeted instance which causes an overwrite of arbitrary cached entries.

What

Synacor Zimbra Collaboration Suite (ZCS) allows an attacker to inject memcache commands into a targeted instance which causes an overwrite of arbitrary cached entries.

Why

The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Synacor Zimbra Collaboration Suite (ZCS) allows an attacker to inject memcache commands into a targeted instance which causes an overwrite of arbitrary cached entries.

Why

The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2022-08-04. Known ransomware campaign use is recorded.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-74 ↗

CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection'). The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.IHighIntegrity impact: A successful attack can cause a major loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-74CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2022-32412Known-exploited evidence recorded

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.

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20220427Security Bulletin 27 Apr 2022

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 27 Apr 2022, published on 27 April 2022. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-442Vulnérabilité dans Zimbra

Une vulnérabilité a été découverte dans Zimbra. Elle permet à un attaquant de provoquer une exécution de code arbitraire à distance et une atteinte à l'intégrité des données.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-291Multiples vulnérabilités dans Zimbra

De multiples vulnérabilités ont été découvertes dans Zimbra. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, un déni de service à distance et une atteinte à l'intégrité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2022-008787Zimbra の collaboration におけるインジェクションに関する脆弱性

Zimbra の collaboration には、インジェクションに関する脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5684현재 악용되고 있는 Exploit(Update. 2022-08-04)

Zimbra Collaboration (ZCS) allows an attacker to inject memcache commands into a targeted instance which causes an overwrite of arbitrary cached entries.

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5637Zimbra 제품 보안 업데이트 권고

Zimbra Collaboration에서 발생하는 계정정보 탈취 취약점 (CVE-2022-27924)

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Mitigation available
Affected
n/a
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Apply updates per vendor instructions.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 20 Apr 2022 · Last source change 1 Oct 2026, 20:28 UTC · CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2022-32412
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCISA ADP
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: knvd.krcert.or.kr/detail?id=62ea8d70d082fd0d2a52dba2.
    Before
    remediation: knvd.krcert.or.kr/detail?id=62ea8d70d082fd0d2a52dba2 · vendor advisory: wiki.zimbra.com/P24 · vendor advisory: wiki.zimbra.com/Security_Center · 1 more references
    After
    vendor advisory: wiki.zimbra.com/P24 · vendor advisory: wiki.zimbra.com/Security_Center · vendor advisory: wiki.zimbra.com/Zimbra_Security_Advisories
    wiki.zimbra.com ↗
  2. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    wiki.zimbra.com ↗
  3. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: knvd.krcert.or.kr/detail?id=62ea8d70d082fd0d2a52dba2.
    Before
    remediation: knvd.krcert.or.kr/detail?id=62ea8d70d082fd0d2a52dba2 · vendor advisory: wiki.zimbra.com/P24 · vendor advisory: wiki.zimbra.com/Security_Center · 1 more references
    After
    vendor advisory: wiki.zimbra.com/P24 · vendor advisory: wiki.zimbra.com/Security_Center · vendor advisory: wiki.zimbra.com/Zimbra_Security_Advisories
    wiki.zimbra.com ↗
  4. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    wiki.zimbra.com ↗
  5. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: knvd.krcert.or.kr/detail?id=62ea8d70d082fd0d2a52dba2.
    Before
    remediation: knvd.krcert.or.kr/detail?id=62ea8d70d082fd0d2a52dba2 · vendor advisory: wiki.zimbra.com/P24 · vendor advisory: wiki.zimbra.com/Security_Center · 1 more references
    After
    vendor advisory: wiki.zimbra.com/P24 · vendor advisory: wiki.zimbra.com/Security_Center · vendor advisory: wiki.zimbra.com/Zimbra_Security_Advisories
    wiki.zimbra.com ↗
  6. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    wiki.zimbra.com ↗
  7. Affected versionsThe structured affected or fixed version information changed.
    Before
    n/a: n/a · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    n/a · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CISA KEV ↗
  8. Affected versionsThe structured affected or fixed version information changed.
    Before
    n/a · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    n/a: n/a · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  9. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    KISA KrCERT/CC ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Remediation guidance recorded
ENISA EUVD · EUVD-2022-32412↗KISA KrCERT/CC remediation guidance↗CISA KEV record↗CVE authority or vendor reference↗Vendor advisory↗Vendor advisory↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2022-27924 · cve.blacktree.nl