CVE-2020-21246Public exploitNetwork attack vector

Stored script execution via unencoded news detail

Published Jun 20, 2023 · Updated Dec 10, 2024

Stored XSS in YiiCMS before 1.2.1 allows remote authenticated users to execute scripts through a crafted news item viewed by another user. The views/news/index.php template inserts model detail directly into the panel body without HTML encoding, preserving attacker-supplied markup. An attacker needs low-privilege access to publish the item, and another user must view it; script execution is limited to that viewer's site context.

CVSS severity5.4
Medium
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in YiiCMS before 1.2.1 allows remote authenticated users to execute scripts through a crafted news item viewed by another user. The views/news/index.php template inserts model detail directly into the panel body without HTML encoding, preserving attacker-supplied markup. An attacker needs low-privilege access to publish the item, and another user must view it; script execution is limited to that viewer's site context.

The record

CVE
CVE-2020-21246
Published
Jun 20, 2023
Updated
Dec 10, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 10, 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.4GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
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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