Security readout for executives and security teams
Plain-English summary
CVE-2019-11825 is a stored or reflected web scripting risk in Synology Calendar's Event Editor before version 2.3.0-0615. A logged-in attacker could place script or HTML in an event title, and another user's browser could process it when viewed. Business impact is mainly session, data, or trust abuse within affected Calendar use.
Executive priority
Treat this as a moderate-priority hygiene fix. It is not listed as actively exploited in the provided sources, but it can affect user trust and browser-side data exposure in shared calendar environments.
Technical view
The CVE describes CWE-79 cross-site scripting in Synology Calendar before 2.3.0-0615. The vulnerable input is the Event Editor title parameter. CVSS 3.1 is 6.5 with network access, low attack complexity, low privileges required, user interaction required, changed scope, and low confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to organizations running Synology Calendar versions earlier than 2.3.0-0615, especially where lower-trust users can create or edit calendar events viewed by others.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector indicates exploitation requires privileges and user interaction, reducing urgency compared with unauthenticated server compromise.
Researcher notes
The public description names only the title parameter and the fixed-before version boundary. It does not provide affected build ranges beyond Synology Calendar before 2.3.0-0615, exploit telemetry, or detailed remediation beyond vendor advisory review and upgrade.
Mitigation direction
- Upgrade Synology Calendar to version 2.3.0-0615 or later.
- Review Synology advisory Synology_SA_19_04 for vendor-specific update guidance.
- Limit Calendar access to trusted users until affected systems are updated.
- Prioritize systems used by many users or shared across teams.
Validation and detection
- Inventory Synology Calendar installations and record installed package versions.
- Confirm no deployed Synology Calendar instance is older than 2.3.0-0615.
- Identify whether untrusted or low-trust users can create calendar event titles.
- Review security monitoring for suspicious calendar content or user-reported script behavior.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2019-11825 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L2.33.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://www.synology.com/security/advisory/Synology_SA_19_04CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.