CVE-2023-26359 Adobe ColdFusion Deserialization of Untrusted Data Vulnerability
Adobe ColdFusion contains a deserialization of untrusted data vulnerability that could result in code execution in the context of the current user.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 21 Aug 2023.
- Rated Critical severity (CVSS 9.8, scored by Vendor).
- It has been in the catalogue for 1,173 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
Adobe ColdFusion versions 2018 Update 15 (and earlier) and 2021 Update 5 (and earlier) are affected by a Deserialization of Untrusted Data vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue does not require user interaction.
Affected Versions
| Product | Versions |
|---|---|
| Adobe ColdFusion | unspecified to CF2018U15, CF2021U5 unspecified to None |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Adobe ColdFusion. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
Fix it
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vulnerability Management - 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
Not Sure If You Are Exposed?
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