CVE-2021-24225Public exploitNetwork attack vector

Authenticated reflected XSS via unsanitized calId

Published Apr 12, 2021 · Updated Aug 3, 2024

Cross-site scripting in Elbtide Advanced Booking Calendar before 1.6.7 allows remote authenticated users to execute script via a crafted calId parameter. The Seasons & Calendars administration page places the unsanitized GET calId value directly in an HTML A tag, allowing attacker-controlled markup and JavaScript to execute in a victim's browser. Exploitation requires a logged-in user to follow a malicious link, with confidentiality and integrity impact in the affected WordPress session but no availability impact.

CVSS severity5.4
Medium
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Elbtide Advanced Booking Calendar before 1.6.7 allows remote authenticated users to execute script via a crafted calId parameter. The Seasons & Calendars administration page places the unsanitized GET calId value directly in an HTML A tag, allowing attacker-controlled markup and JavaScript to execute in a victim's browser. Exploitation requires a logged-in user to follow a malicious link, with confidentiality and integrity impact in the affected WordPress session but no availability impact.

The record

CVE
CVE-2021-24225
Published
Apr 12, 2021
Updated
Aug 3, 2024
Vendor
Elbtide
Product
Advanced Booking Calendar
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=1.6.7 <1.6.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Elbtide · Advanced Booking Calendarversion=1.6.7 <1.6.7

Published CVSS scores

3.5NVDAV:N/AC:M/Au:S/C:N/I:P/A:N
5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Cross-site Scripting (XSS)
T1189Drive-by Compromise

Public exploit references

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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