VulnerabilityPublished 18 Sep 2026

CVE-2026-40534: Synology DiskStation Manager (DSM) · Cross-site Scripting

Affects Synology DiskStation Manager (DSM)Source CVE Database V5

Not known to be exploited · CVSS 5.4 Medium · fixed in 7.3.2-86009-2 : update Synology DiskStation Manager (DSM) when convenient.

Data as of 2 Nov 2026, 10:58 UTC

CVSS 3.1 base score

5.4Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 19% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.3.2-86009-2, 7.2.2-72806-7, 7.2.1-69057-10

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade synology/diskstation-manager to 7.3.2-86009-2, 7.2.2-72806-7 or 7.2.1-69057-10.

Affected software

Product	Affected	Fixed in
SynologyDiskStation Manager (DSM)	Affected >=7.3 <7.3.2-86009-2 >=7.2.2 <7.2.2-72806-7 >=7.2.1 <7.2.1-69057-10	Fixed in–
Synologysynology/diskstation-manager`pkg:rpm/synology/diskstation-manager`Other threats	Affected <7.2.1-69057-10 <7.2.2-72806-7 <7.3.2-86009-2	Fixed in 7.2.1-69057-10 7.2.2-72806-7 7.3.2-86009-2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

In the meantime, restrict access to the affected DSM versions to trusted users only and consider minimizing use of the vulnerable Video API features.

Description

An improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Video API in Synology DiskStation Manager (DSM) before 7.2.1-69057-10, 7.2.2-72806-7 and 7.3.2-86009-2 allows remote authenticated users to read or write limited files when the player is launched.

Impact

Remote authenticated users can exploit this XSS vulnerability to read or write limited files on the affected DSM system when launching the player. This could lead to partial compromise of confidentiality and integrity of data within the scope of the affected component. There is no impact on availability. The vulnerability requires user interaction and privileges, limiting the attack surface.

References

synology.com/en-global/security/advisory/Synology_SA_26_06 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 18 Sep 2026, 11:16 UTC

Technical details

References

Community reviews

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