CVE-2026-34424Known exploitationPublic exploitNetwork attack vector

Unauthenticated code execution via injected header backdoor

Published Apr 9, 2026 · Updated Apr 9, 2026

Embedded malicious code in Nextendweb Smart Slider 3 Pro 3.5.1.35 for WordPress and Joomla allows remote attackers to execute code. In the WordPress build, injected bootstrap code decodes X-Cache-Key header data and passes it directly to shell_exec when a fixed X-Cache-Status value is supplied. Any public page load reaches this pre-authentication path, which runs as the web server user; Joomla also contains remote-code and persistent-backdoor payloads, but its exact trigger is not published.

CVSS severity9.3
Critical
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Embedded malicious code in Nextendweb Smart Slider 3 Pro 3.5.1.35 for WordPress and Joomla allows remote attackers to execute code. In the WordPress build, injected bootstrap code decodes X-Cache-Key header data and passes it directly to shell_exec when a fixed X-Cache-Status value is supplied. Any public page load reaches this pre-authentication path, which runs as the web server user; Joomla also contains remote-code and persistent-backdoor payloads, but its exact trigger is not published.

The record

CVE
CVE-2026-34424
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
Nextendweb
Product
Smart Slider 3
Classifications
CWE-506, T1505.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 7, 2026Exploitation reportedCompromised update infrastructure delivered malicious 3.5.1.35
  2. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  3. Apr 9, 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=3.5.1.35

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Nextendweb · Smart Slider 3version=3.5.1.35

Published CVSS scores

9.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA: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
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-506Embedded Malicious Code
T1505.003Web Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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