CVE-2017-6627 — IOS
HIGHCVE-2017-6627 is a high-severity (CVSS 7.5) CWE-399 vulnerability in cisco ios. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-03-03) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
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…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-03-03. Federal agencies were required to remediate by 2022-03-24.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2017-6627.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2017-6627 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
Affected Products
iosciscoios xeciscoResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every cisco ios deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2017-6627 yet — track the cisco ios advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2017-6627 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.