CVE-2021-38677Network attack vector

Browser data disclosure via reflected script injection

Published Jan 14, 2022 · Updated Sep 17, 2024

Reflected XSS in QNAP QcalAgent before 1.1.7 allows remote attackers to inject malicious code via unspecified vectors. QNAP has not disclosed the affected endpoint, parameter, or encoding failure that reflects untrusted input into a browser-executed context. Exploitation requires user interaction and can disclose browser-accessible data in the affected session without interrupting the service.

CVSS severity5.3
Medium
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in QNAP QcalAgent before 1.1.7 allows remote attackers to inject malicious code via unspecified vectors. QNAP has not disclosed the affected endpoint, parameter, or encoding failure that reflects untrusted input into a browser-executed context. Exploitation requires user interaction and can disclose browser-accessible data in the affected session without interrupting the service.

The record

CVE
CVE-2021-38677
Published
Jan 14, 2022
Updated
Sep 17, 2024
Vendor
Linn Products Limited
Product
QcalAgent
Classifications
CWE-79
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

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.3QNAP Systems, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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