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Advisory record · GHSA-gj26-w59c-29mf

Concrete CMS vulnerable to Remote Code Execution by stored PHP object injection

CVSS 8.9 HighEPSS 0.0069 · 53rd percentile

Published by the GitHub Advisory Database at 4 Mar 2026, 03:31 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
concrete5/concrete5Packagist<9.4.89.4.8
Identifiers
GHSA-gj26-w59c-29mf · CVE-2026-3452 · PKSA-79x2-hpny-rxg9
Weakness (CWE)
CWE-502
Tags
Published
4 Mar 2026
Updated
4 Mar 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Concrete CMS versions below 9.4.8 are vulnerable to remote code execution through stored PHP object injection in the Express Entry List block, via its columns parameter. An attacker who is an authenticated administrator can store serialized data in block configuration that is later unserialized without class restrictions, which can lead to code execution. Upgrade concrete5/concrete5 to version 9.4.8 or later.

Written 3 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
8.9 High 4.0 CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H CNA (ConcreteCMS)
  • CISA KEV Not listed.
  • EPSS 0.0069, the 53rd percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:26 UTC First seen by agentprime
  2. 31 Oct 2026, 14:26 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.