CVE-2021-33501Public exploitNetwork attack vector

Remote code execution via unsanitized URL category

Published Jul 19, 2021 · Updated Aug 3, 2024

Cross-site scripting in Overwolf Client 0.169.0.22 allows remote attackers to execute code via a crafted overwolfstore URL. The Appstore scheme handler inserts an unchecked URL category into an HTML error response rendered by its CEF interface, where script can invoke privileged Overwolf APIs. A user must open the link; the script can write and launch a batch file with that user's privileges.

CVSS severity9.6
Critical
EPSS probability7.91%
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 Overwolf Client 0.169.0.22 allows remote attackers to execute code via a crafted overwolfstore URL. The Appstore scheme handler inserts an unchecked URL category into an HTML error response rendered by its CEF interface, where script can invoke privileged Overwolf APIs. A user must open the link; the script can write and launch a batch file with that user's privileges.

The record

CVE
CVE-2021-33501
Published
Jul 19, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-94, CWE-79, T1203, T1204.001, T1059.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.6NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
9.6SwordBytesCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
9.3NIST NVDAV:N/AC:M/Au:N/C:C/I:C/A:C

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-94Improper Control of Generation of Code ('Code Injection')
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution
T1204.001User Execution: Malicious Link
T1059.003Command and Scripting Interpreter: Windows Command Shell

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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