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Calendar CVE-2019-11820

MEDIUM
Insufficiently Protected Credentials (CWE-522)
2019-05-09 security@synology.com
5.5
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V6 - Authentication Credential protection in transit/storage
Impact

CVSS score of 5.5 (MEDIUM). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required.

Exploit ScenarioDerived

A local attacker with access to the system could obtain user credentials due to weak protection mechanisms.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAI

Information exposure through process environment vulnerability in Synology Calendar before 2.3.3-0620 allows local users to obtain credentials via cmdline. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Hash passwords with strong algorithms (bcrypt, argon2), encrypt credentials in transit and at rest, never log credentials.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Insufficiently Protected Credentials (CWE-522), which allows attackers to obtain user credentials due to weak protection mechanisms. Information exposure through process environment vulnerability in Synology Calendar before 2.3.3-0620 allows local users to obtain credentials via cmdline. Affected products include: Synology Calendar. Version information: before 2.3.3.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

DescriptionNVD

Information exposure through process environment vulnerability in Synology Calendar before 2.3.3-0620 allows local users to obtain credentials via cmdline.

Threat Intelligence Overview

EPSS Score
0.3%
Top 80% exploitable
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.3%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)NVD

cpe:2.3:a:synology:calendar:*:*:*:*:*:*:*:*
CVE-2026-14827 MEDIUM POC
6.8 Jul 27

Stored cross-site scripting (XSS) in the Calendar WordPress plugin prior to version 1.3.18 allows authenticated users wi

CVE-2022-24838 CRITICAL
9.8 Apr 11

Nextcloud Calendar is a calendar application for the nextcloud framework. Rated critical severity (CVSS 9.8), this vulne

CVE-2019-11829 CRITICAL
9.8 Jun 30

OS command injection vulnerability in drivers_syno_import_user.php in Synology Calendar before 2.3.1-0617 allows remote

CVE-2025-66550 MEDIUM POC
5.7 Dec 05

A security vulnerability in Nextcloud Calendar (CVSS 5.7). Risk factors: public PoC available. Vendor patch is available

CVE-2023-45150 MEDIUM POC
4.3 Oct 16

Nextcloud calendar is a calendar app for the Nextcloud server platform. Rated medium severity (CVSS 4.3), this vulnerabi

CVE-2022-22686 HIGH
8.0 Jul 26

Cross-Site Request Forgery (CSRF) vulnerability in webapi component in Synology Calendar before 2.3.4-0631 allows remote

CVE-2021-34812 HIGH
7.5 Jun 18

Use of hard-coded credentials vulnerability in php component in Synology Calendar before 2.4.0-0761 allows remote attack

CVE-2026-29052 MEDIUM
6.9 Mar 05

HumHub Calendar module versions prior to 1.8.11 contain a stored XSS vulnerability in Event Types that allows attackers

CVE-2013-2698 MEDIUM
6.8 May 27

Cross-site request forgery (CSRF) vulnerability in the Calendar plugin before 1.3.3 for WordPress allows remote attacker

CVE-2017-15891 MEDIUM
6.5 Dec 08

Improper access control vulnerability in SYNO.Cal.EventBase in Synology Calendar before 2.0.1-0242 allows remote authent

CVE-2025-66511 MEDIUM
6.5 Dec 05

Unauthenticated attackers can forge meeting-proposal participant tokens in the Nextcloud Calendar app before version 6.0

CVE-2023-48308 MEDIUM
6.5 Dec 22

Nextcloud/Cloud is a calendar app for Nextcloud. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploi

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