CVE-2025-26951Network attack vector

Browser script execution via insufficient input sanitization

Published Apr 15, 2025 · Updated Apr 28, 2026

Stored cross-site scripting in COVERT NINE C9 Blocks 1.7.7 and earlier allows remote authenticated users to inject browser scripts. Public advisories identify insufficient input sanitization and output escaping but do not disclose the affected block, field, or code path. Contributor-level access is required to store a payload, and execution occurs when another user visits the injected page, exposing that user's browser session to attacker-controlled script behavior.

CVSS severity6.5
Medium
EPSS probability0.27%
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 COVERT NINE C9 Blocks 1.7.7 and earlier allows remote authenticated users to inject browser scripts. Public advisories identify insufficient input sanitization and output escaping but do not disclose the affected block, field, or code path. Contributor-level access is required to store a payload, and execution occurs when another user visits the injected page, exposing that user's browser session to attacker-controlled script behavior.

The record

CVE
CVE-2025-26951
Published
Apr 15, 2025
Updated
Apr 28, 2026
Vendor
COVERT NINE
Product
C9 Blocks
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 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=0 <=1.7.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

COVERT NINE · C9 Blocksversion=0 <=1.7.7

Published CVSS scores

6.5PatchstackCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
6.4Wordfence IntelligenceCVSS:3.1/AV:N/AC:L/PR:L/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

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

No public exploit references are available in this record.

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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