Security Experts:

Cisco Patches Critical Flaw in Small Business Router

Cisco has released a firmware update for one of its small business routers to address a critical vulnerability that can be exploited for denial-of-service (DoS) attacks and arbitrary code execution.

The vulnerability, discovered by researchers from GeekPwn, a China-based IoT-focused hacking competition, affects CVR100W Wireless-N VPN routers. The company said there was no evidence of malicious exploitation.

The flaw, tracked as CVE-2017-3882 and described as a buffer overflow, affects the device’s Universal Plug and Play (UPnP) implementation and it can allow an unauthenticated, layer 2-adjacent attacker to execute arbitrary code with root privileges or cause vulnerable routers to reload.Cisco CVR routers vulnerable to hacker attacks

The security hole can be exploited by sending a specially crafted request to the UPnP listening port of the targeted router.

The flaw affects CVR100W Wireless-N VPN routers running a version of the firmware prior to Cisco said no other small business routers are affected. Users can determine which firmware version is running on their device from the product’s web interface.

The same router model is also affected by a medium severity bug that can be exploited by an unauthenticated attacker to bypass the remote management ACL. This security hole has been addressed with the release of version

Cisco on Wednesday also published three other advisories describing high severity vulnerabilities affecting various products.

The networking giant informed customers that several of its Aironet access points are affected by a PnP-related vulnerability that can be exploited for arbitrary code execution with root privileges. While the security hole has been classified “high severity,” Cisco pointed out that there is only a small window for exploitation and the attacker needs to have network access.

The other two flaws, affecting IOS XR and TelePresence Collaboration Endpoint (CE) software, allow a remote, unauthenticated attacker to cause devices to enter a DoS condition.

Patches are available for all vulnerabilities and Cisco says it’s not aware of any in-the-wild attacks where these weaknesses have been exploited.

Related: Cisco Patches Critical Flaw in Aironet Access Points

Related: Actively Exploited Struts Flaw Affects Cisco Products

Related: Cisco Fixes Serious Flaws in Security, Other Products

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.