A critical arbitrary code execution vulnerability is being actively exploited in unpatched Adobe ColdFusion versions 2018 and 2021. A security bulletin was released by Adobe to inform users of this actively exploited vulnerability, along with two other vulnerabilities patched in the same update, a critical severity deserialisation flaw and a memory leak path traversal vulnerability. The actively exploited critical vulnerability was also added to CISA’s Known Exploited Vulnerabilities Catalog due to the high risk of this flaw being exploited in an attack as it is an improper access control vulnerability, which is a frequent attack vector used in cyber attacks. 

The improper access control vulnerability tracked as CVE-2023-26360 has been exploited as a zero-day in limited attacks against Adobe ColdFusion. This vulnerability causes the product to not restrict, or incorrectly restrict, access to a resource. This results in an attacker being able to bypass access control to execute code on the target. The other critical severity vulnerability patched in this update is CVE-2023-26359, which has a CVSS base score of 9.8, revealing it I s considered to be of a higher severity than CVE-2023-26360 which has a CVSS score of 8.6. This vulnerability causes the deserialisation of untrusted data without verifying its validity, which can also lead to arbitrary code execution in the event of an attack, however this flaw is not believed to be currently exploited in the wild. The final vulnerability addressed in this update is the medium severity path traversal flaw tracked as CVE-2023-26361. This vulnerability causes an improper limitation of a pathname to a restricted directory, which can lead to a memory leak when the pathname is resolved to a location outside the restricted directory. 

 These vulnerabilities affect ColdFusion 2018 versions 15 and earlier, and ColdFusion 2021 version 5 and earlier. Users should update to ColdFusion 2018 version 16 or later, or ColdFusion 2021 version 6 or later to apply the security fixed for these flaws. ColdFusion 2016 and ColdFusion 11 have also been found to be vulnerable however these versions are no longer supported by Adobe, so have not received any security updates. End-of-life and unsupported software should not be used in a secure environment as any vulnerabilities found to be affecting these systems will not be patched, and they will remain vulnerable to attacks putting your network and data at risk.