---
id: "CVE-2026-54859"
kind: "vulnerability"
aliases: ["CVE-2026-54859"]
title: "Preservation WordPress plugin: unauthenticated PHP object injection lets attackers run code"
severity: "critical"
cvss: 9.8
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "preservation", "fixed": [], "affected": "<= 1.15", "ecosystem": "wordpress-theme"}]
ecosystems: []
tags: ["package", "php", "preservation", "theme", "unauthenticated", "wordpress"]
not_affected_if: ["managed-hosting-with-patchstack-rule", "plugin-not-installed", "theme-not-installed"]
published_at: "2026-10-29T16:18:10+00:00"
first_seen_at: "2026-10-29T16:25:59+00:00"
updated_at: "2026-10-29T16:32:50+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54859", "first_seen_at": "2026-10-29T16:25:59+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-29T16:32:50+00:00"}]
---

# Preservation WordPress plugin: unauthenticated PHP object injection lets attackers run code

The Preservation WordPress theme (not a plugin), versions 1.15 and earlier, deserializes untrusted data without authentication. Patchstack rates it CVSS 9.8 and says no official patch exists; the exact entry point is not published.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- wordpress-theme:preservation affected <= 1.15 fixed ?

## How to check

In WordPress admin go to Appearance > Themes and check the Preservation theme version; 1.15 or earlier (active or merely installed) is vulnerable. With WP-CLI: wp theme list

## Timeline

- 2026-10-29T16:25:59+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-54859
- 2026-10-29T16:32:50+00:00 analyst — NVD page returned empty; triage said plugin but Patchstack page (reported by johska, 13 Oct 2026) shows it is a theme, <= 1.15, no official patch, Patchstack virtual-patch rule exists for its customers. Not vendor page, so nothing marked verified. No exploitation or PoC found; did not search social.

## Documents

- [advisory] Patchstack: WordPress Preservation Theme <= 1.15 PHP Object Injection https://patchstack.com/database/wordpress/theme/preservation/vulnerability/wordpress-preservation-theme-1-15-php-object-injection-vulnerability

## From the sources

Unauthenticated PHP Object Injection in Preservation <= 1.15 versions.

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