CVE-2017-3859

What it is

A vulnerability in the DHCP code for the Zero Touch Provisioning feature of Cisco ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to a format string vulnerability when processing a crafted DHCP packet for Zero Touch Provisioning. An attacker could exploit this vulnerability by sending a specially crafted DHCP packet to an affected device. An exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition. This vulnerability affects Cisco ASR 920 Series Aggregation Services Routers that are running an affected release of Cisco IOS XE Software (3.13 through 3.18) and are listening on the DHCP server port. By default, the devices do not listen on the DHCP server port. Cisco Bug IDs: CSCuy56385.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

2.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2017-03-22 19:59 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 01:19 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 2.5% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2017-03-22 19:59 UTC

Last modified

2026-06-17 01:19 UTC

Exploit probability

2.5% · EPSS, next 30 days

Weakness

CWE-134

Record status

Modified

Affected

• Cisco iOS Xe 3.13.4s
• Cisco iOS Xe 3.13.5as
• Cisco iOS Xe 3.13.5s
• Cisco iOS Xe 3.13.6as
• Cisco iOS Xe 3.13.6s
• Cisco iOS Xe 3.14.3s
• Cisco iOS Xe 3.14.4s
• Cisco iOS Xe 3.15.2s

Attack profile CVSS 3.0 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2017-3859.md and follow it. Check whether this project is affected by CVE-2017-3859. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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