CVE-2017-6627: high-severity vulnerability in Cisco IOS and Cisco IOS XE
Published · Updated
51Vexday Risk Score
Prioritize patching. It under exploitation confirmed by CISA.
ssvc Actcvss 7.5epss 6.2%
from disclosure to weapon
Published on NVDSep 7
CISA KEV+1638d
exploitation probability
6.2%top 7% of all CVEs
observed exploitation
yesCISA + VulnCheck
Action required by CISAfederal deadline: 2022-03-24
Apply updates per vendor instructions.
In short
A flaw in Cisco IOS and IOS XE allows attackers to send specially crafted UDP packets that get stuck in the device's input queue, slowing down or stopping normal network traffic. This can be exploited remotely without authentication.
Technical detail
UDP socket handling vulnerability in Cisco IOS 15.1/15.2/15.4 and IOS XE 3.14-3.18 where idle sockets remain open, allowing unauthenticated remote attackers to flood input queues via UDP packets destined to port 0, causing interface queue wedge and DoS until 250 packets accumulate. Attack vector is network-based, requires no authentication or user interaction, and results in availability impact through resource exhaustion.
Summary generated and translated by AI from the official description.
A vulnerability in the UDP processing code of Cisco IOS 15.1, 15.2, and 15.4 and IOS XE 3.14 through 3.18 could allow an unauthenticated, remote attacker to cause the input queue of an affected system to hold UDP packets, causing an interface queue wedge and a denial of service (DoS) condition. The vulnerability is due to Cisco IOS Software application changes that create UDP sockets and leave the sockets idle without closing them. An attacker could exploit this vulnerability by sending UDP packets with a destination port of 0 to an affected device. A successful exploit could allow the attacker to cause UDP packets to be held in the input interfaces queue, resulting in a DoS condition. The input interface queue will stop holding UDP packets when it receives 250 packets. Cisco Bug IDs: CSCup10024, CSCva55744, CSCva95506.