dbcve.org
Diskstation ManagerOperating system · Synology

CVE-2021-29088

HIGH · 7.8 CVSS v3.1 Published 2021-06-01
Fix available
A fix is available. Upgrade to 6.2.4-25553 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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 · unedited
Improper limitation of a pathname to a restricted directory ('Path Traversal') in cgi component in Synology DiskStation Manager (DSM) before 6.2.4-25553 allows local users to execute arbitrary code 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 confidence

Path traversal vulnerability in the CGI component of Synology DiskStation Manager allows authenticated local users to escape restricted directories and potentially execute arbitrary code by manipulating file paths in unspecified vectors.

MitigationUpgrade Synology DSM to version 6.2.4-25553 or later to obtain the vendor patch addressing this path traversal vulnerability.

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
Diskstation ManagerOperating system
Affected:< 6.2.4-25553

CVSS 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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify DSM version
    Log into the Synology administrative interface (DSM) and navigate to Control Panel > DSM Update, or run `cat /etc/VERSION` via SSH to retrieve the installed DSM version number.
    Affected if The installed version is lower than 6.2.4-25553 (e.g., 6.2.3, 6.2.2, etc.)
  2. Confirm CGI module is enabled
    In DSM, go to Control Panel > Web Services > Application Portal, or check the web server configuration for CGI/mod_cgi enabled status.
    Affected if CGI execution is enabled on the Synology device, allowing the vulnerable component to process requests.
  3. Verify local user accounts exist
    In DSM, go to Control Panel > User & Group to see if local user accounts are created, or run `synouser --list` via SSH.
    Affected if At least one local authenticated user account exists on the system, which is required to exploit this vulnerability as an authenticated attacker.

The system is affected if the installed DSM version is below 6.2.4-25553 AND CGI functionality is enabled AND local user authentication is configured.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 6.2.4-25553 or later
Fixed in 6.2.4-25553
Interim mitigation

Upgrade Synology DSM to version 6.2.4-25553 or later to obtain the vendor patch addressing this path traversal vulnerability.

Fix this in Diskstation Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-29088 in production — separate from our analysis above.

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What this is

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.

What belongs here
  • 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
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