CyberSecBulletin
CVE-2024-50396NVD status: Analyzed

QTS: Use of Externally-Controlled Format String

Published Updated By the CyberSecBulletin desk

CVE-2024-50396 is a high-severity use of externally-controlled format string vulnerability in QTS from QNAP, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 5.2.1.2930 build 20241025 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 0.67% chance of exploitation within 30 days, higher than 53% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update QTS to 5.2.1.2930 build 20241025 or a later version.
  2. Update QuTS hero to h5.2.1.2929 build 20241025 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.
  5. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
QNAPQTS? up to, but not including, 5.2.1.2930 build 202410255.2.1.2930 build 20241025
QNAPQuTS heroh5.2.x up to, but not including, h5.2.1.2929 build 20241025h5.2.1.2929 build 20241025

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
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

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

Scoring systemScoreSeverityScored by
CVSS 4.07.7HighCNA (qnapsecurity.com.tw)
CVSS 3.18.8HighNVD

Official description

A use of externally-controlled format string vulnerability has been reported to affect several QNAP operating system versions. If exploited, the vulnerability could allow remote attackers to obtain secret data or modify memory. We have already fixed the vulnerability in the following versions: QTS 5.2.1.2930 build 20241025 and later QuTS hero h5.2.1.2929 build 20241025 and later

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

The underlying weakness: Use of Externally-Controlled Format String

The product uses a function that accepts a format string as an argument, but the format string originates from an external source.

How developers prevent this class of flaw

  • Choose a language that is not subject to this flaw.
  • Ensure that all format string functions are passed a static string which cannot be controlled by the user, and that the proper number of arguments are always sent to that function as well. If at all possible, use functions that do not support the %n operator in format strings.
  • Run compilers and linkers with high warning levels, since they may detect incorrect usage.

More Use of Externally-Controlled Format String vulnerabilities (CWE-134)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in QTS

All QTS vulnerabilities

Recent Use of Externally-Controlled Format String vulnerabilities

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