CVE-2026-2121Public exploitNetwork attack vector

Stored XSS via unescaped widget class attribute

Published Mar 21, 2026 · Updated Mar 21, 2026

Stored cross-site scripting in Weaver Show Posts 1.8.1 and earlier allows remote authenticated users to inject scripts through add_class. The Show Posts widget stores the Additional Classes to Wrap Posts value and emits add_class into a page attribute without sufficient sanitization or output escaping. Administrator access is required, and the issue primarily affects multisite sites where administrators lack unfiltered_html; injected scripts execute when a visitor opens the affected page.

CVSS severity4.4
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Weaver Show Posts 1.8.1 and earlier allows remote authenticated users to inject scripts through add_class. The Show Posts widget stores the Additional Classes to Wrap Posts value and emits add_class into a page attribute without sufficient sanitization or output escaping. Administrator access is required, and the issue primarily affects multisite sites where administrators lack unfiltered_html; injected scripts execute when a visitor opens the affected page.

The record

CVE
CVE-2026-2121
Published
Mar 21, 2026
Updated
Mar 21, 2026
Vendor
Weaver Theme
Product
Weaver Show Posts
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Mar 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 21, 2026Record 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=* <=1.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Weaver Theme · Weaver Show Postsversion=* <=1.8.1

Published CVSS scores

4.4WordfenceCVSS:3.1/AV:N/AC:H/PR:H/UI:N/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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