dbcve.org
Diskstation ManagerOperating system · Synology

CVE-2013-6955

HIGH · 10.0 CVSS v2.0 Published 2014-01-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
High EPSS Remotely reachable No privileges 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
webman/imageSelector.cgi in Synology DiskStation Manager (DSM) 4.0 before 4.0-2259, 4.2 before 4.2-3243, and 4.3 before 4.3-3810 Update 1 allows remote attackers to append data to arbitrary files, and consequently execute arbitrary code, via a pathname in the SLICEUPLOAD X-TMP-FILE HTTP header.

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

A path traversal and file injection vulnerability in webman/imageSelector.cgi allows remote unauthenticated attackers to control the X-TMP-FILE HTTP header to append malicious data to arbitrary files on the Synology NAS filesystem, leading to arbitrary code execution.

MitigationUpgrade Synology DSM to version 4.0-2259, 4.2-3243, or 4.3-3810 Update 1 or later. If patching is not feasible immediately, disable or restrict access to the webman interface and imageSelector.cgi through firewall rules or network segmentation.

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:= 4.0= 4.2= 4.3= 4.3-3810

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
Network
Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

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 Synology DSM admin console and go to Control Panel > System > Update & Restore, or run 'grep -i version /etc/VERSION' via SSH to retrieve the installed DSM version number
    Affected if The installed version is 4.0, 4.2, or 4.3-3810 (any build before the fixed updates)
  2. Verify webman module is installed
    Check for the presence of /webman/imageSelector.cgi on the NAS by attempting to access https://[nas-ip]/imageSelector.cgi or checking file existence via SSH at /usr/syno/synoman/webman/cgi/imageSelector.cgi
    Affected if The imageSelector.cgi file exists in the webman directory and responds to requests
  3. Confirm web interface accessibility
    Attempt an HTTP request to the Synology IP on port 5000 or 5001 to verify the DSM web interface is reachable from the network
    Affected if The DSM web interface is accessible from untrusted networks without restriction
  4. Check X-TMP-FILE header handling
    Send a test HTTP request to imageSelector.cgi with a modified X-TMP-FILE header (e.g., X-TMP-FILE: /etc/passwd) using curl -H 'X-TMP-FILE: /etc/passwd' http://[nas-ip]/webman/imageSelector.cgi - observe if the server accepts and processes the header
    Affected if The server accepts arbitrary paths in the X-TMP-FILE header without rejecting or sanitizing the input

The environment is affected if the Synology DSM version is 4.0, 4.2, or 4.3-3810 AND the webman/imageSelector.cgi endpoint is network-accessible, allowing an attacker to manipulate the X-TMP-FILE header for file injection.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Synology DSM to version 4.0-2259, 4.2-3243, or 4.3-3810 Update 1 or later. If patching is not feasible immediately, disable or restrict access to the webman interface and imageSelector.cgi through firewall rules or network segmentation.

Recommended fix High confidence

DSM 4.0-2259, DSM 4.2-3243, or DSM 4.3-3810 Update 1 (or later) depending on the current major version branch

  1. 1. Back up all critical data on the Synology NAS before proceeding with any system upgrade.
  2. 2. Identify the current DSM version installed on the DiskStation Manager.
  3. 3. For DSM 4.0: Upgrade to version 4.0-2259 or later.
  4. 4. For DSM 4.2: Upgrade to version 4.2-3243 or later.
  5. 5. For DSM 4.3: Upgrade to version 4.3-3810 Update 1 or later.
  6. 6. Download the appropriate DSM update from the official Synology download center at https://www.synology.com/en-global/support/download.
  7. 7. Install the update via DSM Control Panel > Update & Restore > DSM Update, or manually apply the .pat file if the automatic update is not available.
  8. 8. After upgrading, verify that the webman/imageSelector.cgi vulnerability is no longer present by confirming the DSM version and checking that the security fix is applied.
Caveat DSM major version upgrades may affect installed packages and configurations; always review Synology package compatibility before upgrading and ensure backups are current

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Diskstation Manager Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2013-6955 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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