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Full vulnerability report · 2024
CVE-2024-45519High confidence

Synacor Zimbra Collaboration Suite (ZCS) Command Execution Vulnerability

Synacor · Zimbra Collaboration Suite (ZCS)

10.0CriticalCVSS 3.1
Recommended action
Mitigate now

CISA confirms exploitation in the wild and lists 2024-10-24 as the remediation due date.

Mitigation available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • CISA confirms exploitation in the wild.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 99.91% 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-2024-41520

CISA KEV mirrored by ENISA

The postjournal service in Zimbra Collaboration (ZCS) before 8.8.15 Patch 46, 9 before 9.0.0 Patch 41, 10 before 10.0.9, and 10.1 before 10.1.1 sometimes allows unauthenticated users to execute commands.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 3 Oct 2024. Evidence sources: cisa_kev.
ENISA score
10.0 · CVSS 3.1
Advisory evidence
1 linked advisory record
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_ncscnl · NCSC-2024-0386Kwetsbaarheden verholpen in Zimbra
Recommended actionMitigate now

CISA confirms exploitation in the wild and lists 2024-10-24 as the remediation due date.

Mitigation available
01

What, why and how

Synacor Zimbra Collaboration Suite (ZCS) contains an unspecified vulnerability in the postjournal service that may allow an unauthenticated user to execute commands.

What

Synacor Zimbra Collaboration Suite (ZCS) contains an unspecified vulnerability in the postjournal service that may allow an unauthenticated user to execute commands.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

What

Synacor Zimbra Collaboration Suite (ZCS) contains an unspecified vulnerability in the postjournal service that may allow an unauthenticated user to execute commands.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

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 2024-10-03.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') → execute code or commands in the affected security context
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-78 ↗

CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command 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/AC:L/AV:N/A:H/C:H/I:H/PR:N/S:C/UI:N

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

ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.AVNetworkAttack vector: The vulnerable component can be reached over a network.AHighAvailability impact: A successful attack can cause a major loss.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.PRNonePrivileges required: The attacker does not need an account or existing privileges.SChangedScope: The attack can affect a component governed by a different security authority.UINoneUser interaction: No action by another user is required.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
NetworkUnauthenticatedRemote code executionCWE-78CISA KEVPublic exploit reference
A

Official authority intelligence

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

ENISA EUVD · EUVD-2024-41520Known-exploited evidence recorded

The postjournal service in Zimbra Collaboration (ZCS) before 8.8.15 Patch 46, 9 before 9.0.0 Patch 41, 10 before 10.0.9, and 10.1 before 10.1.1 sometimes allows unauthenticated users to execute commands.

Official EUVD record ↗
Canadian Centre for Cyber Security · English · AV24-558Zimbra security advisory (AV24-558)

On September 4, 2024, Zimbra published a security advisory to address a vulnerability in the following products: The Cyber Centre has received reports that CVE-2024-45519 may have been exploited.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20241009Security Bulletin 09 Oct 2024

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 09 Oct 2024, published on 9 October 2024. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0742Multiples vulnérabilités dans Synacor Zimbra Collaboration

De multiples vulnérabilités ont été découvertes dans Synacor Zimbra Collaboration. Elles permettent à un attaquant de provoquer un problème de sécurité non spécifié par l'éditeur.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2024-009745Zimbra の collaboration における不正な認証に関する脆弱性

Zimbra の collaboration には、不正な認証に関する脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6303美 CISA 발표 주요 Exploit 정보공유(Update. 2024-10-03)

Synacor Zimbra Collaboration contains an unspecified vulnerability in the postjournal service that may allow an unauthenticated user to execute commands.

Official advisory ↗
NCSC-NL · Dutch · NCSC-2024-0386Kwetsbaarheden verholpen in Zimbra

Door middel van het versturen van een speciaal geprepareerde e-mail naar de SMTP server kan direct code executie worden verkregen op de Zimbra server die bijvoorbeeld gebruikt kan worden om een webshell te plaatsen. Onderzoekers hebben Proof-of-Concept-code gepubliceerd, waarmee de kwetsbaarheid met kenmerk CVE-2024-45519 kan worden aangetoond. Er is een exploit beschikbaar en er zijn signalen van actief misbruik.

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
UPDATE: Het NCSC heeft op Github een tool beschikbaar gesteld die gebruikt kan worden om een eventuele webshell die middels deze kwetsbaarheid is geplaatst te detecteren. Synacor heeft updates uitgebracht om de kwetsbaarheden te verhelpen. Zie bijgevoegde referenties voor meer informatie en de link naar de scantool op Github.
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 2 Oct 2024 · Last source change 3 Feb 2026, 19:27 UTC · CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVE recordCVE.org · 5.2
CVSS sourceCNA
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-2024-41520
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: advisories.ncsc.nl/ncsc-2024-0386.json.
    Before
    remediation: advisories.ncsc.nl/ncsc-2024-0386.json
    After
    no authoritative guidance recorded
    CISA KEV ↗
  2. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    CISA KEV ↗
  3. 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 ↗
  4. 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 ↗
  5. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    NCSC-NL ↗
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-2024-41520↗NCSC-NL remediation guidance↗CISA KEV record↗CVE authority or vendor reference↗Public exploit reference↗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-2024-45519 · cve.blacktree.nl