CVE-2017-12319
A vulnerability in the Border Gateway Protocol (BGP) over an Ethernet Virtual Private Network (EVPN) for Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload, resulting in a denial of service (DoS) condition, or potentially corrupt the BGP routing table, which could result in network instability.
A vulnerability in the Border Gateway Protocol (BGP) over an Ethernet Virtual Private Network (EVPN) for Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload, resulting in a denial of service (DoS) condition, or potentially corrupt the BGP routing table, which could result in network instability. The vulnerability exists due to changes in the implementation of the BGP MPLS-Based Ethernet VPN RFC (RFC 7432) draft between IOS XE software releases. When the BGP Inclusive Multicast Ethernet Tag Route or BGP EVPN MAC/IP Advertisement Route update packet is received, it could be possible that the IP address length field is miscalculated. An attacker could exploit this vulnerability by sending a crafted BGP packet to an affected device after the BGP session was established. An exploit could allow the attacker to cause the affected device to reload or corrupt the BGP routing table; either outcome would result in a DoS. The vulnerability may be triggered when the router receives a crafted BGP message from a peer on an existing BGP session. This vulnerability affects all releases of Cisco IOS XE Software prior to software release 16.3 that support BGP EVPN configurations. If the device is not configured for EVPN, it is not vulnerable. Cisco Bug IDs: CSCui67191, CSCvg52875.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H- securityfocus.com/bid/101676Broken LinkThird Party Advisory
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171103-bgpVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12319US Government Resource
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1677 days
- CVSS
- 5.9 MEDIUM
- EPSS (30-day exploit probability)
- 5.2% · top 8% of all CVEs
- Weakness
- CWE-20
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.