Zero Radar
← feed
CriticalVulnerabilityCVE-2026-54859updated 29 Oct 2026, 20:04 UTC

Preservation plugin lets anyone without login inject malicious PHP objects

Attackers who do not need a password could send specially crafted data to a website using this plugin, which can make the site run harmful code. This can let them take control of or damage the site.

Official, 2 sources
SeverityCriticalCVSS 9.8 of 10
Being exploited?UnclearNo reports either way yet
Fix available?UnclearNo fixed version published in the sources yet
How sure is this?Official, 2 sourcesBacked by an official source

How the attack works simplified

  1. 1Attacker sends payloadCrafted serialized data sent with no login
  2. 2Plugin unserializes inputUntrusted data is processed as PHP objects
  3. 3Malicious object triggers codeGadget chain runs attacker-chosen logic
  4. 4Server compromisedAttacker gains control of the site
  5. ResultAttacker controls the website server

What happened

Unauthenticated PHP Object Injection in the Preservation plugin (versions up to and including 1.15), caused by unsafe deserialization of untrusted input.

Why it is dangerous: A successful attack can lead to remote code execution or full site compromise, and any site running the affected plugin with a public web presence is exposed.

Are you affected?

You are affected if you run the Preservation plugin version 1.15 or earlier on a WordPress site.

Preservation plugin, versions <= 1.15

What to do

  1. Check whether the Preservation plugin is installed and note its version
  2. Deactivate and remove the Preservation plugin if you cannot confirm a fixed version
  3. Check the plugin's official page or GitHub advisory GHSA-6hr3-65pr-wchw for a patched release and update as soon as one is available

Timeline

  1. 29 Oct 2026, 16:18 UTC
    Publicly disclosed
  2. 29 Oct 2026, 16:18 UTC
    Reported by NVD · NVD
  3. 29 Oct 2026, 16:20 UTC
    Picked up by Zero Radar
  4. 29 Oct 2026, 20:04 UTC
    GitHub Advisory reported on it · GitHub Advisory

Sources 2 reports, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
CVE-2026-54859 · GHSA-6hr3-65pr-wchw
CVSS
9.8 / 10
EPSS
0.5% chance of exploitation within 30 days
Disclosed
29 Oct 2026, 16:18 UTC
On Zero Radar
29 Oct 2026, 16:20 UTC (2 min after disclosure)
Last change
29 Oct 2026, 20:04 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

Preservation plugin lets anyone without login inject malicious PHP objects · Zero Radar