Security readout for executives and security teams
Plain-English summary
Synology Calendar had a file upload flaw before version 2.2.2-0532. A logged-in remote user could manipulate an attachment filename to place files outside the intended upload location. The published CVSS score is medium, with integrity impact only.
Executive priority
Treat as a moderate-priority hygiene fix. It is authenticated and medium severity, but file upload path traversal can create operational risk on shared systems. Patch affected Synology Calendar instances during the next maintenance window, sooner if Calendar is exposed to many users or the internet.
Technical view
CVE-2018-13299 is a CWE-23 relative path traversal issue in Synology Calendar Attachment Uploader. The filename parameter allowed remote authenticated users to upload arbitrary files. Affected versions are described as Synology Calendar before 2.2.2-0532. CVSS v3.0 is 4.3: network-accessible, low complexity, low privileges, no user interaction.
Likely exposure
Exposure is limited to environments running Synology Calendar before 2.2.2-0532, especially where authenticated users can reach Calendar remotely. The source bundle does not identify specific DSM versions, appliances, or deployment configurations.
Exploitation context
The provided sources do not report active exploitation, and this CVE is not listed as KEV in the bundle. Exploitation requires authenticated access, reducing broad internet risk, but compromised or low-trust accounts could still abuse the upload path.
Researcher notes
Key constraints are authenticated access and integrity-only CVSS impact. Sources do not establish remote code execution, data theft, unauthenticated access, or active exploitation. Validation should focus on version confirmation, exposed authenticated access, and evidence of abnormal attachment uploads.
Mitigation direction
- Upgrade Synology Calendar to 2.2.2-0532 or later using Synology guidance.
- Restrict Calendar access to trusted users and trusted networks until upgraded.
- Review active Calendar accounts and remove unnecessary access.
- Check Synology advisory for any environment-specific remediation notes.
Validation and detection
- Inventory Synology Calendar installations and record package versions.
- Confirm no deployed instance is older than 2.2.2-0532.
- Review Calendar exposure paths, including internet-facing access and VPN-only access.
- Inspect upload-related logs for unusual filenames or unexpected write locations.
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-23: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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 lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2018-13299 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.3 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
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:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N2.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
4.3MediumVector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.synology.com/security/advisory/Synology_SA_18_54CVE 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.