CVE-2021-38678Network attack vector

User redirection via undisclosed URL validation flaw

Published Jan 14, 2022 · Updated Sep 17, 2024

Open redirect in QNAP QcalAgent before 1.1.7 allows remote attackers to send users to an untrusted site through a crafted link. QNAP has not published the affected endpoint, parameter, or validation error that permits an attacker-controlled destination. Exploitation requires a user to follow the crafted link, after which the browser is redirected to an attacker-chosen page that can host malicious content.

CVSS severity6.1
Medium
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in QNAP QcalAgent before 1.1.7 allows remote attackers to send users to an untrusted site through a crafted link. QNAP has not published the affected endpoint, parameter, or validation error that permits an attacker-controlled destination. Exploitation requires a user to follow the crafted link, after which the browser is redirected to an attacker-chosen page that can host malicious content.

The record

CVE
CVE-2021-38678
Published
Jan 14, 2022
Updated
Sep 17, 2024
Vendor
Linn Products Limited
Product
QcalAgent
Classifications
CWE-601, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record 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=unspecified <1.1.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Linn Products Limited · QcalAgentversion=unspecified <1.1.7

Published CVSS scores

6.1QNAP Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
T1204.001User Execution: Malicious Link

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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