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CriticalVulnerabilityCVE-2026-54858updated 29 Oct 2026, 20:04 UTC

Printy: unauthenticated attackers can run code via crafted data

Printy is software that handles data sent to it. A flaw lets anyone on the internet send specially crafted data that makes the software run commands it should not, without needing a login.

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. 1AttackerSends crafted request without logging in
  2. 2InternetRequest reaches exposed Printy service
  3. 3Printy appUnsafely unserializes the attacker's PHP object
  4. 4ServerInjected object triggers unintended code paths
  5. ResultAttacker may gain control of the server

What happened

Unauthenticated PHP Object Injection in Printy versions 1.13.0 and earlier, caused by unsafe handling of serialized PHP objects in untrusted input.

Why it is dangerous: An attacker who can reach the Printy service without logging in may be able to take control of the server or read and change its data. Anyone running an exposed, affected instance is at risk.

Are you affected?

You are affected if you run Printy version 1.13.0 or earlier and it is reachable from the internet or untrusted networks.

Printy <= 1.13.0

What to do

  1. Check whether you run Printy version 1.13.0 or earlier
  2. Update Printy to a version newer than 1.13.0 as soon as a fixed release is available from the vendor
  3. Restrict access to Printy so it is not exposed to untrusted networks until patched
  4. Watch the GitHub advisory GHSA-x6hf-v9hx-4p8f for fix details

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-2026-54858 · GHSA-x6hf-v9hx-4p8f
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

Printy: unauthenticated attackers can run code via crafted data · Zero Radar