CVE-2019-16027Network attack vector

Authenticated IS-IS interruption via crafted SNMP OID request

Published Jan 26, 2020 · Updated Nov 15, 2024

Denial of service in Cisco IOS XR Software before 6.6.3, 7.0.2, 7.1.1, or 7.2.1 allows remote authenticated users to interrupt IS-IS. The IS-IS process improperly handles SNMP requests for specific OIDs, entering a denial-of-service condition when a crafted query reaches the device. Exploitation requires both IS-IS routing and SNMPv1, SNMPv2c, or SNMPv3 to be configured, and interrupts routing handled by that process.

CVSS severity7.7
High
EPSS probability1.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco IOS XR Software before 6.6.3, 7.0.2, 7.1.1, or 7.2.1 allows remote authenticated users to interrupt IS-IS. The IS-IS process improperly handles SNMP requests for specific OIDs, entering a denial-of-service condition when a crafted query reaches the device. Exploitation requires both IS-IS routing and SNMPv1, SNMPv2c, or SNMPv3 to be configured, and interrupts routing handled by that process.

The record

CVE
CVE-2019-16027
Published
Jan 26, 2020
Updated
Nov 15, 2024
Vendor
ClamAV
Product
Cisco IOS XR Software
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 26, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco IOS XR Softwareversion=unspecified <n/a

Published CVSS scores

7.7Cisco Systems, Inc.CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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