CVE-2020-18658Public exploitNetwork attack vector

Script execution via unfiltered timezone setting

Published Jun 23, 2021 · Updated Aug 4, 2024

Reflected cross-site scripting in GetSimpleCMS 3.3.15 and earlier allows remote attackers to execute script via a crafted timezone setting. The settings.php handler assigns the POSTed TIMEZONE value without filtering and renders it into a quoted HTML context that a double quote can escape. A victim must render the crafted response in a browser; execution remains confined to the GetSimpleCMS origin and the victim's session privileges.

CVSS severity6.1
Medium
EPSS probability1.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected cross-site scripting in GetSimpleCMS 3.3.15 and earlier allows remote attackers to execute script via a crafted timezone setting. The settings.php handler assigns the POSTed TIMEZONE value without filtering and renders it into a quoted HTML context that a double quote can escape. A victim must render the crafted response in a browser; execution remains confined to the GetSimpleCMS origin and the victim's session privileges.

The record

CVE
CVE-2020-18658
Published
Jun 23, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

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

4.3NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NVDCVSS: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')
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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