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CriticalVulnerabilityCVE-2026-54856updated 29 Oct 2026, 20:04 UTC

RexCoin plugin: unauthenticated PHP object injection flaw

Attackers without any login may be able to send specially crafted data to the RexCoin plugin and make the website run their code. This can let them take over 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

What happened

The RexCoin plugin (versions up to and including 1.2.6) contains an unauthenticated PHP Object Injection vulnerability, where untrusted input is unsafely deserialized.

Why it is dangerous: A successful attacker could potentially run arbitrary code or alter site data, compromising the whole website and its visitors. The CVSS severity is critical (9.8).

Are you affected?

You are affected if you run the RexCoin WordPress/PHP plugin at version 1.2.6 or earlier.

RexCoin <= 1.2.6

What to do

  1. Check whether the RexCoin plugin is installed and what version it is
  2. Deactivate or remove the RexCoin plugin if you do not strictly need it
  3. If you must keep it, update to a fixed version once the vendor releases one, and check the GitHub advisory for the latest guidance
  4. Restrict access to the site and monitor logs for unusual requests

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-2026-54856 · GHSA-rxfj-66h4-qpp6
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

RexCoin plugin: unauthenticated PHP object injection flaw · Zero Radar