Authenticated code execution via unrestricted shortcode filters
Published Sep 4, 2025 · Updated Apr 8, 2026
Code injection in Kleor Easy Timer 4.2.1 and earlier allows remote authenticated users to execute code through shortcode attributes. Shortcode handlers accept a user-controlled filter attribute and invoke its named PHP functions without requiring them in the KLEOR_FILTERS allowlist. Editor-level access is required, and successful exploitation runs attacker-selected code with the WordPress server process's privileges.
Summary
What happened
Code injection in Kleor Easy Timer 4.2.1 and earlier allows remote authenticated users to execute code through shortcode attributes. Shortcode handlers accept a user-controlled filter attribute and invoke its named PHP functions without requiring them in the KLEOR_FILTERS allowlist. Editor-level access is required, and successful exploitation runs attacker-selected code with the WordPress server process's privileges.
The record
- CVE
- CVE-2025-9519
- Published
- Sep 4, 2025
- Updated
- Apr 8, 2026
- Vendor
- Kleor
- Product
- Easy Timer
- Classifications
- CWE-94, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 4, 2025CVE publishedPublication date reported by the CVE source.
- 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.
- Affected versionversion=0 <=4.2.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
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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