CVE-2021-29085
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedImproper neutralization of special elements in output used by a downstream component ('Injection') vulnerability in file sharing management component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to read arbitrary files via unspecified vectors.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceAn injection vulnerability in the file sharing management component of Synology DiskStation Manager allows remote attackers to read arbitrary files on the system due to improper neutralization of special elements in user-supplied input. This is essentially a path traversal vulnerability that enables unauthorized file system access without authentication.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 6.2, < 6.2.3-25426-3< 3.1-23033CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Confirm Synology DSM is installedIdentify if the target system runs Synology DiskStation Manager. This is the operating system on Synology NAS devices. Check the system or look for the DSM web interface on port 5000 or 5001.Affected if The system is running Synology DiskStation Manager
-
Determine the DSM versionLog into the DSM web interface, navigate to Control Panel > System > Update & Restore > DSM Update, or connect via SSH and run 'cat /etc/VERSION' to read the installed version number.Affected if Unable to determine the installed DSM version
-
Compare version to affected rangeCheck if the installed version falls within the vulnerable ranges: 6.2 to 6.2.3-25426-2 for standard DSM, or any version below 3.1-23033 for Unified Controller. Versions 6.2.3-25426-3 and later are patched.Affected if Installed version is 6.2 or higher but below 6.2.3-25426-3, or Unified Controller is below 3.1-23033
-
Verify file sharing component is accessibleCheck if file sharing services are enabled on the DSM system. In DSM Control Panel, go to File Services or File Station to confirm the file sharing management component is active.Affected if File sharing services are enabled and accessible on the network
The system is affected if it runs Synology DSM versions 6.2 through 6.2.3-25426-2 (or Unified Controller below 3.1-23033) and has the file sharing component accessible, allowing unauthenticated remote attackers to perform path traversal and read arbitrary files.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data3.1-230336.2.3-25426-3
Upgrade Synology DSM to version 6.2.3-25426-3 or later. If immediate patching is not feasible, restrict network access to the DSM management interface using firewalls or VPN, and disable unnecessary file sharing services.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-29085 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-29085 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data