Critical Cisco Update Flaw Risks Access Point Functionality and Security

• •Over 230 Cisco AP models are affected by a critical memory overflow vulnerability.
• •The log file cnssdaemon.log grows by 5MB daily, risking device bricking.
• •Cisco provides a tool, WLANPoller, for remediation but warns of potential manual fixes.

Cisco has issued a warning regarding a critical flash memory overflow vulnerability affecting over 230 models of its IOS XE-based wireless access points (APs). The issue arises from a recent software update that causes a log file, cnssdaemon.log, to grow by 5MB daily, potentially filling the onboard flash memory. If not addressed, affected APs may fail to download necessary software updates, leading to security vulnerabilities or device bricking. The impacted IOS XE versions include 17.12.4, 17.12.5, 17.12.6, and 17.12.6a. Cisco advises that administrators can use a tool called WLANPoller to automate the remediation process, but warns that if the memory is already full, manual intervention may be required. Experts emphasize the rarity and severity of this issue, highlighting the need for effective vendor vulnerability management. The situation is urgent as the risk of devices entering a boot loop increases with time.