CVE-2025-8607Network attack vector

Stored XSS via unescaped Countdown attributes

Published Aug 21, 2025 · Updated Apr 8, 2026

Stored cross-site scripting in FunnelKit SlingBlocks 1.6.0 and earlier allows remote authenticated users to inject scripts through Countdown attributes. The Countdown block accepts user-controlled attributes without sufficient input sanitization and renders them without adequate output escaping. Contributor-level access is required to store a payload, which executes whenever a visitor opens the injected page.

CVSS severity6.4
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 FunnelKit SlingBlocks 1.6.0 and earlier allows remote authenticated users to inject scripts through Countdown attributes. The Countdown block accepts user-controlled attributes without sufficient input sanitization and renders them without adequate output escaping. Contributor-level access is required to store a payload, which executes whenever a visitor opens the injected page.

The record

CVE
CVE-2025-8607
Published
Aug 21, 2025
Updated
Apr 8, 2026
Vendor
FunnelKit
Product
SlingBlocks
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 21, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 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 <=1.6.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

FunnelKit · SlingBlocksversion=0 <=1.6.0

Published CVSS scores

6.4WordfenceCVSS: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.

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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