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CriticalVulnerabilityCVE-2026-62001updated 29 Oct 2026, 20:04 UTC

Marcell: unauthenticated PHP object injection can let attackers run code

Attackers without any login can send specially crafted data to the Marcell site and potentially take control of it. Anyone running an affected version should update or restrict access quickly.

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. 1AttackerNeeds no login or account
  2. 2Crafted requestSends malicious serialized data
  3. 3Marcell appUnserializes untrusted input
  4. 4ServerInjected objects execute on server
  5. ResultAttacker may control the server

What happened

An unauthenticated PHP Object Injection flaw affects Marcell versions up to and including 1.2.14, allowing untrusted input to be unserialized into PHP objects.

Why it is dangerous: Successful exploitation could allow an attacker to run arbitrary code or alter data on the server, and the flaw requires no authentication, so any internet-exposed site running Marcell is at risk.

Are you affected?

You are affected if you run Marcell version 1.2.14 or earlier.

Marcell <= 1.2.14

What to do

  1. Check whether your Marcell version is 1.2.14 or earlier
  2. Look for an updated Marcell release or vendor advisory and install it as soon as available
  3. If no fix is available yet, restrict or disable public access to the affected Marcell installation until it is patched

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-2026-62001 · GHSA-j53q-mmvf-4h7v
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

Marcell: unauthenticated PHP object injection can let attackers run code · Zero Radar