Security readout for executives and security teams
Plain-English summary
Synology Office had a stored cross-site scripting issue tied to file names. An authenticated user could create a malicious file name that may run script in another user’s browser when viewed in the affected title tooltip. The issue is medium severity because it needs login access and user interaction, but it can still affect confidentiality, integrity, and availability in the browser session.
Executive priority
Treat this as a moderate-priority hygiene fix. It is not reported as actively exploited in the provided sources, but shared document systems are trust boundaries. Patch older Synology Office deployments promptly, especially where partners, contractors, or broad employee groups have accounts.
Technical view
CVE-2018-8924 is CWE-79 in Synology Office before 3.0.3-2143. The CVSS 3.0 vector is AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L, score 6.5. The reported injection point is the Title Tooltip handling of a malicious file name, allowing arbitrary web script or HTML by remote authenticated users.
Likely exposure
Exposure is likely limited to Synology Office deployments older than 3.0.3-2143 where authenticated users can create, upload, rename, or share files. Internet exposure increases urgency, but the source bundle does not identify specific deployment patterns, vulnerable configurations, or affected CPEs.
Exploitation context
The source bundle does not cite active exploitation, and the CVE is not marked as KEV. Exploitation requires authenticated access and user interaction, which reduces broad unauthenticated risk but still matters in shared office environments with many internal or external collaborators.
Researcher notes
The key constraints are authenticated access, required user interaction, and a malicious file name rendered through Title Tooltip. The bundle does not provide exploit details, CPEs, broad product matrix, or indicators of compromise. Validation should focus on version confirmation and reachable collaboration workflows, not exploit reproduction.
Mitigation direction
- Upgrade Synology Office to version 3.0.3-2143 or later.
- Review the Synology advisory for any deployment-specific guidance.
- Restrict Synology Office access to trusted authenticated users.
- Limit external collaboration until affected instances are updated.
- Monitor for suspicious file names or unexpected Office activity.
Validation and detection
- Inventory Synology Office versions across all Synology systems.
- Confirm no production instance is older than 3.0.3-2143.
- Identify who can create, rename, upload, or share Office files.
- Review logs for unusual file activity around shared documents.
- Verify update completion through Synology package or asset records.
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-2018-8924 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 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/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:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L2.33.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
6.5MediumVector: CVSS:3.0/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/zh-tw/support/security/Synology_SA_18_12CVE 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.