Security readout for executives and security teams
Plain-English summary
This vulnerability affects Synology DiskStation Manager before 6.2.3-25426-3. A remote attacker could read arbitrary files through the file sharing management component. The main business risk is unauthorized disclosure of sensitive NAS data. The source bundle does not show confirmed active exploitation.
Executive priority
Treat this as a high-priority confidentiality risk for NAS environments. It does not indicate system takeover, but arbitrary file read can expose sensitive business, customer, or operational data without authentication according to the CVSS vector.
Technical view
CVE-2021-29085 is a CWE-74 injection issue in Synology DSM’s file sharing management component. CVSS 3.1 is 8.6, with network attack vector, low complexity, no privileges, no user interaction, changed scope, and high confidentiality impact. Vectors are unspecified in the provided sources.
Likely exposure
Organizations running Synology DSM versions before 6.2.3-25426-3 are potentially exposed, especially where DSM or file sharing management is reachable from untrusted networks. The bundle does not identify specific models, configurations, or CPEs.
Exploitation context
The CVE is not listed as KEV in the supplied bundle, and no cited source confirms active exploitation. Exploit mechanics are not described; the available evidence only states remote arbitrary file read via unspecified vectors.
Researcher notes
Evidence is limited to the CVE record and Synology advisory reference. The affected component is named, but attack vectors, affected model list, exploit availability, and indicators are not provided in the source bundle.
Mitigation direction
- Upgrade affected Synology DSM systems to 6.2.3-25426-3 or later where applicable.
- Review Synology advisory Synology_SA_20_26 for supported fixed versions and product-specific guidance.
- Prioritize remediation for Internet-facing or externally reachable DSM systems.
- If upgrade is delayed, reduce untrusted access to DSM management and file sharing services.
Validation and detection
- Inventory Synology DSM systems and record exact DSM versions.
- Flag DSM versions earlier than 6.2.3-25426-3 for remediation review.
- Confirm whether DSM or file sharing management is reachable from untrusted networks.
- Review storage access logs for unusual file reads; supplied sources provide no IoCs.
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-74: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-2021-29085 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
- High
- CVSS
- 8.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/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:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.6HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.synology.com/security/advisory/Synology_SA_20_26CVE 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 Special Elements in Output Used by a Downstream Component ('Injection')
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.