Jacqueline WordPress theme: PHP Object Injection via unauthenticated requests
Summary
The WordPress theme Jacqueline up to and including version 2.22 contains a PHP Object Injection flaw (CWE-502, deserialization of untrusted data). An unauthenticated remote attacker can submit crafted data that the theme unserializes, which may allow manipulation of server-side processing and harmful actions on the web server. Patchstack and CISA SSVC data rate the impact as total, and the CVSS score is 9.8.
Affected
- ThemeREX Jacqueline WordPress theme, versions up to and including 2.22
- Default configuration: unaffected (per CNA record, default state of affected versions described as n/a)
Fixed in
Unknown. No vendor or Patchstack fixed version was confirmed. Unverified indicators: ThemeForest lists v2.27.0 as current; VulDB states the flaw is fixed in 2.23 or later.
Workaround
Unknown. No vendor or Patchstack workaround was found.
- If the theme is unused, remove it.
- Restrict access to the WordPress admin area.
- Consider virtual patching via a web application firewall until an update is available.
Exploitation
- Not listed in CISA KEV.
- CISA SSVC: exploitation none, automatable yes, technical impact total.
- EPSS score 0.00304.
- Patchstack describes the vulnerability as highly dangerous and expected to be exploited; no public proof of concept was found in the research, which does not prove that none exists.
Our recommendation
- Check whether the Jacqueline theme is installed on any WordPress site, including inactive installations.
- Update to the latest version from the vendor as soon as a fixed release is confirmed, and verify the fix with the vendor.
- If the theme is not needed, remove it.
- Apply a web application firewall rule or virtual patch if an update is delayed.
- Monitor web server logs for unusual requests to the theme.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Patchstack advisory patchstack.com
- OpenCVE CVE-2026-78531 app.opencve.io
- VulDB CVE-2026-78531 vuldb.com
- ThemeForest Jacqueline theme themeforest.net
- Strix CVE-2026-78531 www.strix.ai
- Vulners RAPID7 CVE-2026-78531 vulners.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, 19:26.
Original description (NVD)
Unauthenticated PHP Object Injection in Jacqueline <= 2.22 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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