CVE-2026-22899Network attack vector

Authenticated service crash via NULL pointer dereference

Published Jun 10, 2026 · Updated Jun 10, 2026

NULL pointer dereference in utilRequest.cgi in QNAP File Station 5 before 5.5.6.5208 allows remote authenticated users to crash the service. The CGI request handler dereferences a NULL pointer during request processing, causing a segmentation fault; the triggering field and invalid state are undisclosed. Any low-privileged account can reach the handler over the network, and the documented consequence is service interruption rather than data access or modification.

CVSS severity6.5
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in utilRequest.cgi in QNAP File Station 5 before 5.5.6.5208 allows remote authenticated users to crash the service. The CGI request handler dereferences a NULL pointer during request processing, causing a segmentation fault; the triggering field and invalid state are undisclosed. Any low-privileged account can reach the handler over the network, and the documented consequence is service interruption rather than data access or modification.

The record

CVE
CVE-2026-22899
Published
Jun 10, 2026
Updated
Jun 10, 2026
Vendor
Linn Products Limited
Product
File Station 5
Classifications
CWE-476, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.5.0 <5.5.6.5208

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Linn Products Limited · File Station 5version=5.5.0 <5.5.6.5208

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
1.3QNAP Systems, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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