CVE-2021-24331Public exploitNetwork attack vector

Stored XSS via unsanitized scroll settings

Published Jun 1, 2021 · Updated Aug 3, 2024

Stored XSS in Smooth Page Scroll Up/Down Buttons before 1.4 allows remote authenticated users to execute script through crafted plugin settings. The option-saving handler accepts psb_distance, psb_buttonsize, and psb_speed after client-side-only validation, then persists the values without server-side sanitization. A WordPress administrator account and a user who loads the affected output are required; the injected script runs in that user’s browser context.

CVSS severity4.8
Medium
EPSS probability0.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stored XSS in Smooth Page Scroll Up/Down Buttons before 1.4 allows remote authenticated users to execute script through crafted plugin settings. The option-saving handler accepts psb_distance, psb_buttonsize, and psb_speed after client-side-only validation, then persists the values without server-side sanitization. A WordPress administrator account and a user who loads the affected output are required; the injected script runs in that user’s browser context.

The record

CVE
CVE-2021-24331
Published
Jun 1, 2021
Updated
Aug 3, 2024
Vendor
Senff – a11n
Product
Smooth Page Scroll Up/Down Buttons
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jun 1, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=1.4 <1.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Senff – a11n · Smooth Page Scroll Up/Down Buttonsversion=1.4 <1.4

Published CVSS scores

4.8NISTCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.5NISTAV:N/AC:M/Au:S/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo