Secuno
ENNL
Book demo

CVE-2020-3118

Cisco IOS XR Software Discovery Protocol Format String

8.8 HIGHActively exploited (CISA KEV)EPSS 11.7%
  1. Published5 Feb 2020
  2. Added to CISA KEV3 Nov 2021
  3. Remediation due3 May 2022
Actively exploited (CISA KEV)

Cisco IOS XR improperly validates string input from certain fields in Cisco Discovery Protocol messages. Exploitation could allow an unauthenticated, adjacent attacker to execute code with administrative privileges or cause a reload on an affected device.

Added to KEV: 3 Nov 2021Federal remediation due: 3 May 2022

Description

A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a reload on an affected device. The vulnerability is due to improper validation of string input from certain fields in Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to cause a stack overflow, which could allow the attacker to execute arbitrary code with administrative privileges on an affected device. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

CVSS 3.1 breakdown

Attack vectorAdjacent
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Cisco iOS XR≥ 6.6.0 < 6.6.12 · ≥ 7.0.0 < 7.0.2 · 5.2.5 · 6.4.2

Remediation

Fixed in
Cisco iOS XR≥ 6.6.12

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-1078158.5
MariaDB server is a community developed fork of MySQL server. From 10.6.1 until…
CVE-2026-195708.8
The LE Audio Broadcast Sink in subsys/bluetooth/audio/bap_broadcast_sink.c copies…
CVE-2026-1079099.1
A heap-based out-of-bounds write in the ws_read_frame function (src/bolt/ws.c) and the…
CVE-2026-1079089.8
A heap-based out-of-bounds write in the BoltReadHandler function (src/bolt/bolt_api.c)…
CVE-2026-823448.1
IBM Guardium Data Protection 12.0, 12.1 is vulnerable to a heap-based buffer overflow…
CVE-2026-823358.1
IBM Guardium Data Protection 12.0, 12.1, 12.2 is vulnerable to a heap-based buffer…

Frequently asked

Is CVE-2020-3118 being actively exploited?

Yes. CVE-2020-3118 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021.

How severe is CVE-2020-3118?

CVE-2020-3118 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 11.7% probability of exploitation.

Which products are affected by CVE-2020-3118?

Affected products include Cisco iOS XR.

How do I fix CVE-2020-3118?

Upgrade affected software to a fixed version, for example Cisco iOS XR 6.6.12 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2020-3118 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.