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CriticalVulnerabilityCVE-2026-62131updated 29 Oct 2026, 20:34 UTC

Zoho Flow lets outsiders run code on servers without logging in

Attackers who do not have an account can send specially crafted data to Zoho Flow and make it run commands it should never run. This can let them take control of the system that runs it.

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 requestNo login or account needed
  2. 2App unserializes inputUntrusted data is processed as PHP objects
  3. 3Malicious object triggers codeCrafted object runs unintended actions
  4. 4Server compromisedAttacker gains control of the host
  5. ResultAttacker controls the server

What happened

Zoho Flow versions up to and including 2.14.5 contain an unauthenticated PHP object injection flaw, where untrusted input is unserialized and can trigger dangerous PHP object behavior.

Why it is dangerous: Because no login is required, anyone who can reach a vulnerable Zoho Flow instance could potentially run code, read or change data, and take over the host, with a critical CVSS score of 9.8.

Are you affected?

You are affected if you run Zoho Flow version 2.14.5 or earlier.

Zoho Flow <= 2.14.5

What to do

  1. Check your installed Zoho Flow version and confirm whether it is 2.14.5 or earlier
  2. Check the GitHub advisory GHSA-6pvh-h9mv-qrhc and Zoho's vendor channels for a patched release and update as soon as one is available
  3. If no patch is available yet, restrict network access to the Zoho Flow instance and limit it to trusted users
  4. Review logs for unusual or unauthenticated requests to Zoho Flow endpoints

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, 20:34 UTC
    GitHub Advisory reported on it · GitHub Advisory

Sources 2 reports, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
CVE-2026-62131 · GHSA-6pvh-h9mv-qrhc
CVSS
9.8 / 10
EPSS
0.3% 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, 20:34 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

Zoho Flow lets outsiders run code on servers without logging in · Zero Radar