No exploitation reported

CVE-2019-1977

No exploitation reported by the sources we read.

Published2019-08-30
WeaknessCWE-371

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A vulnerability within the Endpoint Learning feature of Cisco Nexus 9000 Series Switches running in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an endpoint device in certain circumstances. The vulnerability is due to improper endpoint learning when packets are received on a specific port from outside the ACI fabric and destined to an endpoint located on a border leaf when Disable Remote Endpoint Learning has been enabled. This can result in a Remote (XR) entry being created for the impacted endpoint that will become stale if the endpoint migrates to a different port or leaf switch. This results in traffic not reaching the impacted endpoint until the Remote entry can be relearned by another mechanism.

Timeline

dates in UTC

2019-08-3009:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2019-1977?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2019-1977?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Cisco nx-osversion to verify

Branch	Affected	Fixed in	Source
12.3	= 12.3\(1h\)	no fix published	NVD
13.1	= 13.1\(2m\)	no fix published	NVD
13.1	= 13.1\(2o\)	no fix published	NVD
13.1	= 13.1\(2p\)	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

tools.cisco.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2024-11-21
OpenCVESSVC decisionnone—
CNACVSS 3.06.8read 2026-10-23
NVDCVSS 3.07.5read 2026-10-23
NVDCVSS 2.04.3read 2026-10-23
CNAweakness (CWE)CWE-371read 2026-10-23
NVDweakness (CWE)CWE-371read 2026-10-23
FIRST EPSSEPSS score1.5 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2019-08-30
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2019-1977?

Is CVE-2019-1977 actively exploited?

Active exploitation of CVE-2019-1977 has not been confirmed. Its EPSS score was 1.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-1977?

CVE-2019-1977 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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