Security Resilience

CVE-2017-12319

Cisco Ios 15.4\(1\)s

CISA KEVActive ExploitationEUVD Exploited
Published
27 March 2018
Modified
12 January 2026
KEV Added
03 March 2022
Patch / advisory
CVSS Score v3.1 5.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.052 92th percentile
Risk Priority 75 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2017-12319 is a medium-severity Improper Input Validation (CWE-20) vulnerability in Cisco Ios. Its CVSS base score is 5.9 (Medium).

Operationally, ranked in the top 8% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A vulnerability in the Border Gateway Protocol (BGP) over Ethernet Virtual Private Network (EVPN) implementation within Cisco IOS XE Software stems from improper handling of BGP MPLS-Based Ethernet VPN (RFC 7432) updates between software releases. Specifically, the IP address length field can be miscalculated when processing Inclusive Multicast Ethernet Tag Route or EVPN MAC/IP Advertisement Route packets. This affects all IOS XE releases prior to 16.3 that have BGP EVPN configurations enabled; devices without EVPN configuration are not impacted.

An unauthenticated remote attacker who has already established a BGP session with an affected device can send a crafted BGP update packet to trigger the flaw. Successful exploitation may cause the device to reload, producing a denial-of-service condition, or corrupt the BGP routing table, leading to network instability. The attack requires an existing session and does not involve authentication or user interaction.

Cisco Security Advisory cisco-sa-20171103-bgp and associated bug IDs (CSCui67191, CSCvg52875) recommend upgrading to IOS XE release 16.3 or later for affected BGP EVPN deployments. The vulnerability is also tracked in the CISA Known Exploited Vulnerabilities catalog, indicating confirmed real-world exploitation activity.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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,…

more

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.

CWE(s)
KEV Date Added
03 March 2022

Related Threats

CVEs Like This One

CVE-2018-0154Same product: Cisco 1000 Integrated Services Routerboth on KEV
CVE-2017-12234Same product: Cisco 1000 Integrated Services Routerboth on KEV
CVE-2017-12233Same product: Cisco 1000 Integrated Services Routerboth on KEV
CVE-2018-0159Same product: Cisco Asr 901-12C-F-Dboth on KEV
CVE-2017-12237Same product: Cisco 1000 Integrated Services Routerboth on KEV
CVE-2018-0179Same product: Cisco 1000 Integrated Services Routerboth on KEV
CVE-2018-0180Same product: Cisco 1000 Integrated Services Routerboth on KEV
CVE-2017-12240Same product: Cisco 1000 Integrated Services Routerboth on KEV
CVE-2020-3161Same product: Cisco 8831both on KEV
CVE-2017-12235Same product: Cisco Iosboth on KEV

Affected Assets

cisco
ios
15.4\(1\)s
cisco
ios xe
≤ 16.3

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

A.8.25 mandates security requirements, secure coding guidelines, checkpoints, testing (incl. code scans) and developer training in the SDLC, which reaches a slice of input validation defects but leaves the majority (incomplete enforcement, second-order inputs, parser differentials, post-validation canonicalization) unaddressed as in the SA-3 and A.8.28 anchors.

blocks

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

blocks

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-20, a class-level weakness, and none of its children carries one either.

References