How severe is CVE-2023-39303?

CVE-2023-39303 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2023-39303 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-39303?

CVE-2023-39303 primarily affects Qnap Qts. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-39303?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2023-39303 have an EU (EUVD) identifier?

Yes. CVE-2023-39303 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-43035.

When was CVE-2023-39303 published?

CVE-2023-39303 was published on 2024-02-02 and last updated on 2026-06-17.

CVE-2023-39303

CVE-2023-39303 is a medium-severity vulnerability in Qnap Qts with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2023-43035
Weakness: CWE-287
Affected product: Qnap Qts
Published: 2024-02-02
Last modified: 2026-06-17

Description

An improper authentication vulnerability has been reported to affect several QNAP operating system versions. If exploited, the vulnerability could allow users to compromise the security of the system via a network. We have already fixed the vulnerability in the following versions: QTS 5.1.3.2578 build 20231110 and later QuTS hero h5.1.3.2578 build 20231110 and later QuTScloud c5.1.5.2651 and later

Frequently asked questions

What is CVE-2023-39303?: An improper authentication vulnerability has been reported to affect several QNAP operating system versions. If exploited, the vulnerability could allow users to compromise the security of the system via a network. We have already fixed the vulnerability in the following versions: QTS 5.1.3.2578 build 20231110 and later QuTS hero h5.1.3.2578 build 20231110 and later QuTScloud c5.1.5.2651 and later
How severe is CVE-2023-39303?: CVE-2023-39303 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2023-39303 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-39303?: CVE-2023-39303 primarily affects Qnap Qts. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-39303?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2023-39303 have an EU (EUVD) identifier?: Yes. CVE-2023-39303 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-43035.
When was CVE-2023-39303 published?: CVE-2023-39303 was published on 2024-02-02 and last updated on 2026-06-17.

References

https://www.qnap.com/en/security-advisory/qsa-23-33

Affected products (16)

cpe:2.3:o:qnap:qts:5.1.0.2348:build_20230325:*:*:*:*:*:*
cpe:2.3:o:qnap:qts:5.1.0.2399:build_20230515:*:*:*:*:*:*
cpe:2.3:o:qnap:qts:5.1.0.2418:build_20230603:*:*:*:*:*:*
cpe:2.3:o:qnap:qts:5.1.0.2444:build_20230629:*:*:*:*:*:*
cpe:2.3:o:qnap:qts:5.1.0.2466:build_20230721:*:*:*:*:*:*
cpe:2.3:o:qnap:qts:5.1.1.2491:build_20230815:*:*:*:*:*:*
cpe:2.3:o:qnap:qts:5.1.2.2533:build_20230926:*:*:*:*:*:*
cpe:2.3:o:qnap:qts:5.1.3.2578:-:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.1.0.2409:build_20230525:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.1.0.2424:build_20230609:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.1.0.2453:build_20230708:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.1.0.2466:build_20230721:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.1.1.2488:build_20230812:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.1.2.2534:build_20230927:*:*:*:*:*:*
cpe:2.3:o:qnap:quts_hero:h5.1.3.2578:-:*:*:*:*:*:*
cpe:2.3:o:qnap:qutscloud:c5.1.0.2498:build_20230822:*:*:*:*:*:*

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Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
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CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →