Security readout for executives and security teams
Plain-English summary
Synology Video Station had a server-side request forgery issue that could let a remote authenticated user make the system send requests to internal network resources. This is moderate business risk where Video Station is exposed to untrusted or broadly privileged users.
Executive priority
Treat as a moderate-priority remediation item. Prioritize internet-facing or shared Synology deployments and any environment where the device can reach sensitive internal systems.
Technical view
CVE-2021-33181 is CWE-918 in the Video Station webapi component before 2.4.10-1632. The CVSS 3.1 score is 6.6 with network access, low complexity, high privileges, no user interaction, and changed scope. Vectors are unspecified in the supplied sources.
Likely exposure
Exposure is most likely in environments running Synology Video Station before 2.4.10-1632 where authenticated remote users can reach the webapi component. Internal services reachable from the Synology device are the main concern.
Exploitation context
The bundle does not show CISA KEV listing or other evidence of active exploitation. Exploitation requires authentication with high privileges, but no user interaction. The sources do not provide public exploit details or affected configuration specifics.
Researcher notes
The public bundle identifies SSRF in webapi but leaves vectors unspecified. Validation should focus on version, authentication exposure, network placement, and internal reachability. Do not assume unauthenticated exploitation from these sources.
Mitigation direction
- Review Synology advisory Synology_SA_21_04 for the vendor-approved fix.
- Upgrade Video Station from versions before 2.4.10-1632 to a fixed vendor-supported release.
- Restrict Video Station access to trusted users and networks.
- Reduce internal network reachability from Synology devices where operationally possible.
- Monitor Synology logs for unusual authenticated webapi activity.
Validation and detection
- Inventory Synology devices running Video Station.
- Confirm installed Video Station version is not before 2.4.10-1632.
- Check whether Video Station webapi is reachable from untrusted networks.
- Review accounts with Video Station access, especially high-privilege users.
- Identify sensitive intranet services reachable from affected Synology devices.
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-918: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. 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 lookupCloud metadata behavior lookup
The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-33181 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
- 6.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/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:H/UI:N/S:C/C:L/I:L/A:L2.33.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.6MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://www.synology.com/security/advisory/Synology_SA_21_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.
Server-Side Request Forgery (SSRF)
Server-Side Request Forgery (SSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.