CVE-2025-30273: QNAP Systems QTS · Out-of-bounds Write
Affects QNAP Systems QTSSource CVE Database V5
Not known to be exploited · CVSS 7.1 High : upgrade to 5.3.0 soon.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.3.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 29 Aug 2025
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.
What to do
Upgrade QNAP Systems QTS to 5.3.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| QNAP Systems Inc. QTS | Affected
| Fixed in
|
AI-suggested
European organizations should immediately verify their QNAP NAS device versions and upgrade to QTS 5.2.5.3145 or later, or QuTS hero h5.2.5.3138 or later, to remediate this vulnerability. Beyond patching, organizations should enforce strong password policies and multi-factor authentication (MFA) for all user accounts on QNAP devices to reduce the risk of credential compromise. Network segmentation should be applied to isolate NAS devices from direct internet exposure, limiting access to trusted internal networks or VPNs only. Regular monitoring of NAS device logs for unusual access patterns or failed login attempts can help detect potential exploitation attempts early. Organizations should also conduct periodic vulnerability assessments and penetration testing focused on NAS devices to identify and remediate any residual security gaps. Finally, maintaining up-to-date backups stored offline or in immutable storage will mitigate the impact of potential data corruption or ransomware attacks leveraging this vulnerability.
Description
An out-of-bounds write vulnerability has been reported to affect several QNAP operating system versions. If a remote attacker gains a user account, they can then exploit the vulnerability to modify or corrupt memory. We have already fixed the vulnerability in the following versions: QTS 5.2.5.3145 build 20250526 and later QuTS hero h5.2.5.3138 build 20250519 and later