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VulnerabilityPublished

CVE-2025-33039: QNAP Systems Qsync Central · Unthrottled Resource Allocation

Affects QNAP Systems Qsync CentralSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High : upgrade to 5.0.0 soon.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 4.0 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Oct 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 Qsync Central to 5.0.0.

Affected software

ProductAffectedFixed in
QNAP Systems Inc. Qsync CentralAffected
  • >=4.0.0 <5.0.0
Fixed in
  • 5.0.0

AI-suggested

European organizations should prioritize upgrading Qsync Central to version 5.0.0.1 or later, where the vulnerability is fixed. If you cannot patch yet, implement strict access controls to limit user account creation and monitor for unusual resource consumption patterns indicative of exploitation attempts. Employ network segmentation to isolate Qsync Central servers from less trusted network zones and restrict remote access to authorized personnel only. Enhance logging and alerting on resource usage metrics within Qsync Central to detect early signs of resource exhaustion. Conduct regular audits of user accounts to identify and disable inactive or suspicious accounts to reduce the attack surface. Additionally, implement multi-factor authentication (MFA) to protect user accounts from compromise, thereby mitigating the risk of exploitation by unauthorized actors. Consider deploying rate limiting or resource quotas at the infrastructure level if possible, to prevent any single user from monopolizing system resources. Finally, maintain an incident response plan tailored to availability disruptions caused by resource exhaustion attacks.

Description

An allocation of resources without limits or throttling vulnerability has been reported to affect Qsync Central. If a remote attacker gains a user account, they can then exploit the vulnerability to prevent other systems, applications, or processes from accessing the same type of resource. We have already fixed the vulnerability in the following version: Qsync Central 5.0.0.1 ( 2025/07/09 ) and later

References

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