CVE-2023-32975VulnerabilityPublished 8 Dec 2023Updated 27 May 2025

CVE-2023-32975: QNAP Systems QTS · Buffer Overflow

Affects QNAP Systems QTSSource CVE Database V5

Not known to be exploited · CVSS 4.9 Medium : upgrade to 5.2.0 or 5.1.0 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

4.9Medium

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

EPSS: 0.8% chance of exploitation in 30 days – higher than 58% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.2.0, 5.1.0

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

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

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: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 8 Dec 2023
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 2026-10-25.

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 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 QNAP Systems QTS to 5.2.0 or 5.1.0.

Affected software

Product	Affected	Fixed in
QNAP Systems Inc. QTS	Affected >=5.0.0 <5.1.0 >=5.1.0 <5.2.0	Fixed in 5.1.0 5.2.0

AI-suggested

European organizations should prioritize upgrading QNAP QTS devices to the patched versions listed by the vendor: QTS 5.0.1.2514 or later, QTS 5.1.2.2533 or later, QuTS hero h5.0.1.2515 or later, and QuTS hero h5.1.2.2534 or later. If you cannot patch yet, organizations should enforce strict network segmentation to isolate NAS devices from untrusted networks and restrict administrative access to trusted hosts only. Implement multi-factor authentication (MFA) for administrator accounts to reduce the risk of credential compromise. Regularly audit and monitor administrative access logs for suspicious activity. Disable any unnecessary network services on QNAP devices to reduce the attack surface. Employ network-level protections such as firewalls and intrusion detection/prevention systems (IDS/IPS) to detect and block anomalous traffic targeting NAS devices. Additionally, maintain regular backups of critical data stored on QNAP devices to enable rapid recovery in case of service disruption. Finally, educate administrators on secure credential management and the importance of timely patching.

Description

A buffer copy without checking size of input vulnerability has been reported to affect several QNAP operating system versions. If exploited, the vulnerability could allow authenticated administrators to execute code via a network. We have already fixed the vulnerability in the following versions: QTS 5.0.1.2514 build 20230906 and later QTS 5.1.2.2533 build 20230926 and later QuTS hero h5.0.1.2515 build 20230907 and later QuTS hero h5.1.2.2534 build 20230927 and later

Impact

For European organizations using QNAP NAS devices running vulnerable QTS versions, this vulnerability could lead to denial of service or system instability if exploited, potentially disrupting critical file storage, backup, and sharing services. Since QNAP devices are widely used in small to medium enterprises, educational institutions, and some larger organizations for centralized data management, an outage could affect business continuity and data availability. Although exploitation requires administrator credentials, insider threats or compromised admin accounts could leverage this flaw to disrupt operations. The lack of confidentiality or integrity impact reduces the risk of data theft or tampering directly via this vulnerability, but availability impact alone can have significant operational consequences. Given the network-exposed nature of NAS devices, especially if accessible remotely or poorly segmented, the risk of exploitation increases. European organizations with regulatory requirements for data availability and uptime (e.g., GDPR mandates on data integrity and availability) could face compliance challenges if this vulnerability leads to service disruptions.

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #11
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
Docker Security (opens in a new tab)
XML Security (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.1 (opens in a new tab)
V14.1.2 (opens in a new tab)
V13.3.1 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Overflow Buffers (opens in a new tab)
Client-side Injection-induced Buffer Overflow (opens in a new tab)
Filter Failure through Buffer Overflow (opens in a new tab)
MIME Conversion (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

qnap.com/en/security-advisory/qsa-23-07 (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Jul 2025, 04:24 UTC

WeaknessesCWE-120

Technical details

References

Community reviews

Related threats