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Diskstation Manager CVE-2021-29086

HIGH
Information Exposure (CWE-200)
2021-06-23 security@synology.com
7.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V14 - Data Protection Data exposure prevention
MITRE ATT&CK

2 techniques across 2 tactics: Collection, Discovery

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

Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could access sensitive data that should not be disclosed by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 1.2% exploitation probability (EPSS)

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AnalysisAI

Exposure of sensitive information to an unauthorized actor vulnerability in webapi component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to obtain sensitive. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Minimize information in error messages, implement proper access controls, encrypt sensitive data at rest and in transit.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Exposure of Sensitive Information (CWE-200), which allows attackers to access sensitive data that should not be disclosed. Exposure of sensitive information to an unauthorized actor vulnerability in webapi component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to obtain sensitive information via unspecified vectors. Affected products include: Synology Diskstation Manager, Synology Diskstation Manager Unified Controller. Version information: before 6.2.3.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

DescriptionNVD

Exposure of sensitive information to an unauthorized actor vulnerability in webapi component in Synology DiskStation Manager (DSM) before 6.2.3-25426-3 allows remote attackers to obtain sensitive information via unspecified vectors.

Threat Intelligence Overview

EPSS Score
1.2%
Top 36% exploitable
Data Quality
2 sources
Confidence: Low

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 1.2%
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
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)NVD

cpe:2.3:o:synology:diskstation_manager:*:*:*:*:*:*:*:*
cpe:2.3:o:synology:diskstation_manager_unified_controller:*:*:*:*:*:*:*:*
CVE-2013-6955 CRITICAL POC
10.0 Jan 09

webman/imageSelector.cgi in Synology DiskStation Manager (DSM) 4.0 before 4.0-2259, 4.2 before 4.2-3243, and 4.3 before

CVE-2017-5753 MEDIUM POC
5.6 Jan 04

Systems with microprocessors utilizing speculative execution and branch prediction may allow unauthorized disclosure of

CVE-2017-15889 HIGH POC
8.8 Dec 04

Command injection vulnerability in smart.cgi in Synology DiskStation Manager (DSM) before 5.2-5967-5 allows remote authe

CVE-2017-14491 CRITICAL POC
9.8 Oct 04

Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execut

CVE-2017-9554 MEDIUM POC
5.3 Jul 24

An information exposure vulnerability in forget_passwd.cgi in Synology DiskStation Manager (DSM) before 6.1.3-15152 allo

CVE-2013-6987 HIGH POC
7.5 Dec 31

Multiple directory traversal vulnerabilities in the FileBrowser components in Synology DiskStation Manager (DSM) before

CVE-2021-3156 HIGH POC
7.8 Jan 26

Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege

CVE-2018-8897 HIGH POC
7.8 May 08

A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) wa

CVE-2018-1160 CRITICAL POC
9.8 Dec 20

Netatalk before 3.1.12 is vulnerable to an out of bounds write in dsi_opensess.c. Rated critical severity (CVSS 9.8), th

CVE-2021-26566 CRITICAL POC
9.0 Feb 26

Insertion of sensitive information into sent data vulnerability in synorelayd in Synology DiskStation Manager (DSM) befo

CVE-2020-27648 CRITICAL POC
9.0 Oct 29

Improper certificate validation vulnerability in OpenVPN client in Synology DiskStation Manager (DSM) before 6.2.3-25426

CVE-2021-26564 HIGH POC
8.7 Feb 26

Cleartext transmission of sensitive information vulnerability in synorelayd in Synology DiskStation Manager (DSM) before

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