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Download Station CVE-2017-11156

HIGH
Incorrect Default Permissions (CWE-276)
2017-08-14 security@synology.com
Privilege Escalation RCE Synology Download Station
7.8
CVSS 3.0 · NVD
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Vulnerability Assessment

Weakness
CWE
CWE-276
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V13 - Configuration Default permission hardening
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

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Impact

CVSS score of 7.8 (HIGH). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. EPSS exploitation probability: 0.80%.
Exploit ScenarioDerived

A local attacker with access to the system could access resources due to overly permissive default settings.
This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.8% exploitation probability (EPSS)

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AnalysisAI

Synology Download Station 3.8.x before 3.8.5-3475 and 3.x before 3.5-2984 uses weak permissions (0777) for ui/dlm/btsearch directory, which allows remote authenticated users to execute arbitrary code. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Set restrictive default permissions, follow principle of least privilege, review defaults during deployment.

Affects your stack

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Technical ContextAI · show details

This vulnerability is classified as Incorrect Default Permissions (CWE-276), which allows attackers to access resources due to overly permissive default settings. Synology Download Station 3.8.x before 3.8.5-3475 and 3.x before 3.5-2984 uses weak permissions (0777) for ui/dlm/btsearch directory, which allows remote authenticated users to execute arbitrary code by uploading an executable via unspecified vectors. Affected products include: Synology Download Station. Version information: before 3.8.5.

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  • Exploit and PoC references, threat intelligence from 22 sources
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Severity by source

NVD PRIMARY 7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

Synology Download Station 3.8.x before 3.8.5-3475 and 3.x before 3.5-2984 uses weak permissions (0777) for ui/dlm/btsearch directory, which allows remote authenticated users to execute arbitrary code by uploading an executable via unspecified vectors.

Threat Intelligence Overview

EPSS Score
0.8%
Top 26% exploitable
Data Quality
3 sources
Confidence: Low
NVD CVE.org EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.8%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

40
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +39
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Privilege Escalation HIGH

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)CVE.org

cpe:2.3:a:synology:download_station:3.2-2295:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.3-2382:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.3-2383:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.3-2386:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2477:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2478:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2480:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2485:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2486:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2489:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2490:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2514:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2555:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2557:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.4-2558:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.5-2638:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.5-2705:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.5-2706:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.5-2955:*:*:*:*:*:*:*
cpe:2.3:a:synology:download_station:3.5-2956:*:*:*:*:*:*:*
+ 13 more

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CVE-2021-34810 HIGH
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Improper privilege management vulnerability in cgi component in Synology Download Station before 3.8.16-3566 allows remo
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Improper neutralization of special elements used in a command ('Command Injection') vulnerability in task management com
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8.4 Oct 15

Incorrect permission assignment in QNAP Download Station (all builds prior to 5.10.1.312 or 5.11.2.321) lets a local att
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Cross-site scripting (XSS) vulnerability in the "Create download task via file upload" feature in Synology Download Stat
CVE-2015-6913 MEDIUM POC
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Cross-site scripting (XSS) vulnerability in the "Create download task via URL" feature in Synology Download Station befo
CVE-2021-33184 HIGH
7.7 Jun 01

Server-Side request forgery (SSRF) vulnerability in task management component in Synology Download Station before 3.8.15
CVE-2024-38640 HIGH
7.0 Sep 06

A cross-site scripting (XSS) vulnerability has been reported to affect Download Station. Rated high severity (CVSS 7.0),
CVE-2017-11149 MEDIUM
6.5 Aug 14

Server-side request forgery (SSRF) vulnerability in Downloader in Synology Download Station 3.8.x before 3.8.5-3475 and

CVE-2026-39989 MEDIUM
5.3 Oct 15

Server-side request forgery in QNAP Download Station allows a low-privileged authenticated user to make the NAS applicat
CVE-2021-34811 MEDIUM
4.3 Jun 18

Server-Side Request Forgery (SSRF) vulnerability in task management component in Synology Download Station before 3.8.16
CVE-2025-58463 LOW
2.3 Nov 07

A relative path traversal vulnerability has been reported to affect Download Station. Rated low severity (CVSS 2.3), thi
CVE-2025-58465 LOW
2.2 Nov 07

A cross-site scripting (XSS) vulnerability has been reported to affect Download Station. Rated low severity (CVSS 2.2),

Same weakness CWE-276 – Incorrect Default Permissions

View all
CVE-2013-0632 CRITICAL POC
9.8
CVE-2017-11610 HIGH POC
8.8
CVE-2022-22948 MEDIUM POC
6.5
CVE-2017-8625 HIGH POC
8.8
CVE-2026-87886 HIGH
7.8
CVE-2016-5425 HIGH POC
7.8
CVE-2024-55215 CRITICAL POC
9.8
CVE-2024-57604 CRITICAL POC
9.8

Same technique Privilege Escalation

View all
CVE-2024-0012 CRITICAL POC
9.3
CVE-2025-47812 CRITICAL POC
10.0
CVE-2013-0422 CRITICAL POC
9.8
CVE-2024-9474 MEDIUM POC
6.9
CVE-2017-5689 CRITICAL POC
9.8
CVE-2021-20021 CRITICAL POC
9.8
CVE-2017-12635 CRITICAL POC
9.8

References

Advisories & patches
ADVISORY https://www.synology.com/en-global/support/security/Synology_SA_17_28_Download_Station

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