CyberSecBulletin
CVE-2023-39296NVD status: Modified

QTS: Improperly Controlled Modification of Object Prototype Attributes

Published Updated By the CyberSecBulletin desk

CVE-2023-39296 is a high-severity improperly controlled modification of object prototype attributes vulnerability in QTS from QNAP, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 5.1.3.2578 build 20231110 as the first without the flaw, so updating QTS to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.56% chance of exploitation within 30 days, higher than 76% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update QTS to 5.1.3.2578 build 20231110 or a later version.
  2. Update QuTS hero to h5.1.3.2578 build 20231110 or a later version.
  3. Read the advisory on qnap.com for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
QNAPQTS5.1.x up to, but not including, 5.1.3.2578 build 202311105.1.3.2578 build 20231110
QNAPQuTS heroh5.1.x up to, but not including, h5.1.3.2578 build 20231110h5.1.3.2578 build 20231110

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.5HighCNA (qnapsecurity.com.tw)
CVSS 3.17.5HighNVD

Official description

A prototype pollution vulnerability has been reported to affect several QNAP operating system versions. If exploited, the vulnerability could allow users to override existing attributes with ones that have incompatible type, which may lead to a crash 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

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improperly Controlled Modification of Object Prototype Attributes

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

How developers prevent this class of flaw

  • By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
  • By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
  • When handling untrusted objects, validating using a schema can be used.

More Improperly Controlled Modification of Object Prototype Attributes vulnerabilities (CWE-1321)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in QTS

All QTS vulnerabilities

Recent Improperly Controlled Modification of Object Prototype Attributes vulnerabilities

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