CVE-2021-42549Network attack vector

Reflected XSS via unescaped search input

Published Dec 13, 2021 · Updated Aug 4, 2024

Reflected XSS in Lets-Box before 1.15.3 allows remote attackers to inject scripts through the WordPress plugin's search function. The search path returns attacker-controlled input in generated page output without sufficient sanitization or output escaping. Execution requires a visitor to follow a crafted link, and the injected script runs in that visitor's browser under the affected site's origin.

CVSS severity4.7
Medium
EPSS probability0.73%
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 Lets-Box before 1.15.3 allows remote attackers to inject scripts through the WordPress plugin's search function. The search path returns attacker-controlled input in generated page output without sufficient sanitization or output escaping. Execution requires a visitor to follow a crafted link, and the injected script runs in that visitor's browser under the affected site's origin.

The record

CVE
CVE-2021-42549
Published
Dec 13, 2021
Updated
Aug 4, 2024
Vendor
WP Cloud Plugins
Product
Lets-Box
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 <1.15.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WP Cloud Plugins · Lets-Boxversion=unspecified <1.15.3

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
4.7NCSC.chCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/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')
T1203Exploitation for Client Execution

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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