CVE-2021-24214Public exploitNetwork attack vector

Unauthenticated reflected XSS via unescaped login error

Published May 5, 2021 · Updated Aug 3, 2024

Reflected XSS in Jonathan Daggerhart's OpenID Connect Generic Client 3.8.0 and 3.8.1 allows remote attackers to run script via a crafted login error. The login form inserts the login-error query value into its error output without sanitizing or escaping it. Default configuration and no authentication suffice, but a victim must open the crafted login URL; script runs in the WordPress origin.

CVSS severity6.1
Medium
EPSS probability1.63%
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 Jonathan Daggerhart's OpenID Connect Generic Client 3.8.0 and 3.8.1 allows remote attackers to run script via a crafted login error. The login form inserts the login-error query value into its error output without sanitizing or escaping it. Default configuration and no authentication suffice, but a victim must open the crafted login URL; script runs in the WordPress origin.

The record

CVE
CVE-2021-24214
Published
May 5, 2021
Updated
Aug 3, 2024
Vendor
Jonathan Daggerhart
Product
OpenID Connect Generic Client
Classifications
CWE-79, T1189
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

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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=3.8.0 <3.8.0*
  2. Affected versionversion=3.8.2 <3.8.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Jonathan Daggerhart · OpenID Connect Generic Clientversion=3.8.0 <3.8.0*; version=3.8.2 <3.8.2

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/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.

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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')
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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