CVE-2025-53593: QNAP Systems QTS · Stack-based Buffer Overflow
Affects QNAP Systems QTSSource CVE Database V5
Not known to be exploited · CVSS 1.2 Low : upgrade to 5.2.7.3256 build 20250913 when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 29% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.2.7.3256 build 20250913, h5.3.1.3250 build 20250912, h5.2.7.3256 build 20250913
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:UExploitation evidence
Disclosed: evidence found.
CVE published 2 Jan 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.
What to do
Upgrade QTS to 5.2.7.3256 build 20250913; QuTS hero to h5.3.1.3250 build 20250912 or h5.2.7.3256 build 20250913.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| QNAP Systems Inc.QTS | Affected
| Fixed in
|
| QNAP Systems Inc.QuTS hero | Affected
| Fixed in
|
AI-suggested
European organizations using QNAP QTS 5.2.x should immediately verify their device firmware versions and upgrade to the fixed versions: QTS 5.2.7.3256 build 20250913 or later, or the corresponding QuTS hero builds. Beyond patching, organizations should enforce strict administrative access policies, including multi-factor authentication (MFA) for all administrator accounts to reduce the risk of credential compromise. Network segmentation should be applied to isolate NAS devices from general user networks and limit exposure to potential attackers. Monitoring and logging administrative access and unusual system behavior can help detect attempts to exploit this vulnerability. Regular vulnerability assessments and penetration testing should include checks for outdated QNAP firmware. Additionally, organizations should review and harden their NAS device configurations, disabling unnecessary services and restricting remote management access to trusted IPs only. Backup strategies should be validated to ensure data availability in case of service disruption caused by exploitation attempts.
Description
A buffer overflow vulnerability has been reported to affect several QNAP operating system versions. If a remote attacker gains an administrator account, they can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following versions: QTS 5.2.7.3256 build 20250913 and later QuTS hero h5.2.7.3256 build 20250913 and later QuTS hero h5.3.1.3250 build 20250912 and later