Printy WordPress theme: Unauthenticated PHP Object Injection
Summary
The WordPress theme Printy up to and including version 1.13.0 contains a PHP Object Injection flaw (CWE-502) that can be triggered without authentication over the network. An attacker can manipulate serialized data processed by the site, which may lead to harmful actions on the server, depending on the installed plugins and code available for chaining. The vulnerability is rated critical with CVSS 9.8, and Patchstack expects exploitation in mass campaigns, although no exploitation has been confirmed so far.
Affected
- Printy WordPress theme, versions <= 1.13.0
- Companion plugin ThemeREX Addons may be involved; the advisory does not state whether the flaw is in the theme or the plugin
- Vendor and product naming differs between sources (VulDB lists "meREX Printy Plugin")
Fixed in
Unknown. No patched version has been confirmed in the sources reviewed. The ThemeForest listing shows a newer release line (1.16.0), but this does not confirm that it fixes CVE-2026-54858.
Workaround
- No vendor-confirmed workaround available.
- Deactivate and remove the Printy theme and ThemeREX Addons if they are not essential.
- Block public access to the admin area and non-essential endpoints at the WAF level; a WAF is a stopgap, not a fix.
- Review web server logs for unusual requests.
Exploitation
- No evidence of exploitation in the wild found; CISA KEV listing not confirmed.
- No public proof of concept found in the sources checked.
- CISA SSVC assessment: Exploitation none, Automatable yes, Technical Impact total.
Our recommendation
- Inventory all Printy and ThemeREX Addons installations, including staging sites, and record their versions.
- Treat any site running version 1.13.0 or lower, or with an unknown version, as vulnerable.
- Apply the workarounds above immediately and remove the theme where it is not required.
- Check the Patchstack advisory and the ThemeREX changelog for a fixed version; escalate to ThemeREX support if none is listed.
- Do not use nulled copies of the theme, as they usually cannot receive vendor updates.
- Monitor the CISA KEV catalogue and the Patchstack entry for updates and review logs regularly.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Patchstack advisory patchstack.com
- VulDB entry 428517 vuldb.com
- Vulners CVE-2026-54858 vulners.com
- ThemeREX Printy documentation doc.themerex.net
- ThemeForest Printy listing themeforest.net
- ThemeREX Printy product page themerex.net
- Strix CVE-2026-54858 www.strix.ai
- CVE triage issue (CISA KEV status, automated) github.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 30 Oct 2026, 16:05.
Original description (NVD)
Unauthenticated PHP Object Injection in Printy <= 1.13.0 versions.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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