CVE-2021-1243

5.3 MEDIUM 1% exploit odds Fix listed

What it is

A vulnerability in the Local Packet Transport Services (LPTS) programming of the SNMP with the management plane protection feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to allow connections despite the management plane protection that is configured to deny access to the SNMP server of an affected device. This vulnerability is due to incorrect LPTS programming when using SNMP with management plane protection. An attacker could exploit this vulnerability by connecting to an affected device using SNMP. A successful exploit could allow the attacker to connect to the device on the configured SNMP ports. Valid credentials are required to execute any of the SNMP requests.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 1.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-02-04 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:31 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 1.3% in the next 30 days (EPSS).
Severity: 5.3 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-02-04 17:15 UTC
Last modified: 2026-06-17 03:31 UTC
Exploit probability: 1.3% · EPSS, next 30 days
Weakness: CWE-284 · Improper access control
Record status: Modified

Affected

Cisco iOS Xr < 6.6.4
Cisco iOS Xr < 7.0.2
Cisco iOS Xr 6.7.1
Cisco iOS Xr 7.0.11
Cisco iOS Xr 7.1.0
Cisco iOS Xr 7.2.0

Attack profile CVSS 3.1 · 5.3

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2021-1243.md and follow it. Check whether this project is affected by CVE-2021-1243. 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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Fix and advisories

References

NVD record · CVE.org record