CVE-2026-81557
A NVD · · CVE-2026-81557
Admiralty grading (A–F · 1–6)
Source reliability
- A Completely reliable
- B Usually reliable
- C Fairly reliable
- D Not usually reliable
- E Unreliable
- F Cannot be judged
Information credibility
- 1 Confirmed
- 2 Probably true
- 3 Possibly true
- 4 Doubtful
- 5 Improbable
- 6 Cannot be judged
NATO Admiralty (AJP-2.1) grades confidence, independent of the risk score. Cross-source corroboration isn't tracked for non-CVE news, so single-source items are capped at a lower credibility number; a low number does not imply low quality.
Key metrics
- CVSS
- 5.4
- EPSS
- 0%
Key insight
The entry contains only patch and version information; there is no indication of active exploitation, a public exploit, or specific attacker TTPs.
Description
CVE-2026-81557 affects Synology DiskStation Manager (DSM) in versions before 7.3.2-86009-5 and 7.4.1-90080-1. The flaw is an improper neutralization of user input during web page generation in the DSMNotify component. A remote authenticated attacker can thereby read or write specific files in a targeted manner. Exploitation requires valid credentials, which raises the risk especially for internet-exposed DSM instances with weak account management. At the time of reporting there is no indication of active exploitation in the wild or a public exploit; the details originate from the NVD entry.
Risk score
- cvss base
- 54.00
- kev bonus
- 0.00
- epss bonus
- 0.00
- poc bonus
- 0.00
- raw before weight
- 54.00
- industry weight
- 1.21
- freshness factor
- 1.00
- exploitability factor
- 1.00
- days old
- 0.00
- vendor mismatch penalty
- 0.00
Path: operational
MITRE ATT&CK mapping
4 TTPsProcedure details
| Technique | Tactic | Procedure | Conf. | Source |
|---|---|---|---|---|
| T1190 Exploit Public-Facing Application | Initial Access | Attackers exploit CVE-2026-81557, an improper input neutralization flaw in the DSMNotify component of Synology DSM's web management interface, to compromise the appliance and gain unauthorized file read/write capabilities on the NAS. | high | llm |
| T1078 Valid Accounts | Unknown | The vulnerability requires the attacker to be a remote authenticated user of DSM, so adversaries leverage compromised or legitimately obtained DSM credentials to authenticate before exploiting the DSMNotify flaw. | medium | llm |
| T1005 Data from Local System | Collection | Once the DSMNotify input handling is abused, the attacker can read specific files stored on the Synology DiskStation Manager system, enabling collection of sensitive local data from the NAS. | medium | llm |
| T1505.003 Web Shell | Persistence | Because the flaw allows writing specific files on the DSM appliance, an attacker could write malicious content into web-accessible locations to establish persistent server-side execution. | low | llm |