CVE-2025-30265: QNAP Systems QTS · Buffer Overflow
Affects QNAP Systems QTSSource CVE Database V5
Not known to be exploited · CVSS 2.3 Low : upgrade to 5.3.0 when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 31% 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:P/PR:L/UI:N/VC:N/VI:N/VA:L/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 the QTS version running on their QNAP devices and upgrade to version 5.2.5.3145 or later (or QuTS hero h5.2.5.3138 or later) to remediate the vulnerability. Beyond patching, organizations should enforce strict access controls and credential management to minimize the risk of attackers obtaining user accounts. Implement multi-factor authentication (MFA) for NAS access where supported to reduce the likelihood of credential compromise. Regularly audit user accounts and permissions to ensure least privilege principles are applied. Network segmentation should be employed to restrict access to NAS devices only to trusted internal networks or VPN users. Monitoring and alerting on anomalous NAS activity can help detect exploitation attempts early. Finally, organizations should maintain up-to-date backups and have incident response plans ready to address potential denial of service or data availability issues stemming from exploitation attempts.
Description
A buffer overflow 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 memory or crash processes. 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