VulnerabilityPublished 11 Feb 2026

CVE-2025-47205: QNAP Systems QTS · NULL Pointer Dereference

Affects QNAP Systems QTSSource CVE Database V5

Not known to be exploited · CVSS 5.1 Medium : upgrade to 5.2.8.3332 build 20251128 when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score

5.1Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.2.8.3332 build 20251128, h5.2.8.3321 build 20251117

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: High
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: High: The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 QTS to 5.2.8.3332 build 20251128; QuTS hero to h5.2.8.3321 build 20251117.

Affected software

Product	Affected	Fixed in
QNAP Systems Inc.QTS	Affected =>=5.2.0 <5.3.0	Fixed in 5.2.8.3332 build 20251128
QNAP Systems Inc.QuTS hero	Affected ≥ h5.2.x, < h5.2.8.3321 build 20251117	Fixed in h5.2.8.3321 build 20251117

AI-suggested

To mitigate CVE-2025-47205, European organizations should immediately upgrade all affected QNAP QTS devices to the patched versions: QTS 5.2.8.3332 build 20251128 or later, and QuTS hero h5.2.8.3321 build 20251117 or later. Beyond patching, organizations must enforce strict access controls on administrative accounts, including implementing strong, unique passwords and multi-factor authentication (MFA) where supported. Network segmentation should be applied to isolate NAS management interfaces from general user networks and the internet, reducing exposure to credential theft. Regular auditing and monitoring of administrative access logs can help detect unauthorized attempts early. Disable any unnecessary services or remote management features to minimize attack surface. Additionally, organizations should conduct periodic vulnerability assessments and penetration testing focused on NAS devices to identify potential privilege escalation paths that could lead to exploitation. Backup strategies should be reviewed to ensure data availability in case of DoS-induced outages. Finally, user training on phishing and credential security can help prevent initial compromise of administrator accounts.

Description

CVE-2025-47205 is a medium-severity NULL pointer dereference vulnerability affecting QNAP QTS operating system versions 5.2.x. An attacker with administrator privileges can exploit this flaw to cause a denial-of-service (DoS) condition, disrupting system availability. The vulnerability does not require user interaction and has a CVSS 4.0 base score of 5.1, indicating moderate risk. It has been fixed in QTS 5.2.8.

Impact

For European organizations, the primary impact of CVE-2025-47205 is the potential for denial-of-service attacks on QNAP NAS devices, which are widely used for data storage, backup, and file sharing. Disruption of these services can lead to operational downtime, loss of productivity, and potential delays in critical business processes. Industries relying heavily on NAS devices for continuous data availability, such as healthcare, finance, and manufacturing, may experience significant operational impacts. Although the vulnerability does not directly compromise data confidentiality or integrity, the DoS condition can indirectly affect business continuity and service level agreements. Additionally, if administrative credentials are compromised, attackers could leverage this vulnerability to exacerbate the impact by causing system outages. The risk is heightened in environments where QNAP devices are accessible over the network without adequate segmentation or where administrative interfaces are exposed externally. European organizations with remote or hybrid work models may also face increased exposure if remote management is enabled without sufficient protections.

CWE-476NULL Pointer Dereference (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #13OWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product dereferences a pointer that it expects to be valid but is NULL.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Requirements
Select a programming language that is not susceptible to these issues.
Implementation
Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

qnap.com/en/security-advisory/qsa-26-05 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 18 Feb 2026, 15:19 UTC

WeaknessesCWE-476

Technical details

References

Community reviews

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