CVE-2021-24276Public exploitNetwork attack vector

Reflected XSS via unsanitized options tab

Published May 5, 2021 · Updated Aug 3, 2024

Reflected XSS in Contact Form by Supsystic before 1.7.15 allows remote attackers to execute script via a crafted options-page URL. The options page inserts the tab query parameter into an HTML attribute without sanitization, so attacker-controlled attribute syntax reaches the response. Exploitation requires an authenticated WordPress administrator to open the crafted URL, and the script then runs in that administrator's browser context.

CVSS severity6.1
Medium
EPSS probability16.04%
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 Contact Form by Supsystic before 1.7.15 allows remote attackers to execute script via a crafted options-page URL. The options page inserts the tab query parameter into an HTML attribute without sanitization, so attacker-controlled attribute syntax reaches the response. Exploitation requires an authenticated WordPress administrator to open the crafted URL, and the script then runs in that administrator's browser context.

The record

CVE
CVE-2021-24276
Published
May 5, 2021
Updated
Aug 3, 2024
Vendor
Supsystic
Product
Contact Form by Supsystic
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 5, 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=1.7.15 <1.7.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Supsystic · Contact Form by Supsysticversion=1.7.15 <1.7.15

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

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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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