7.7
HIGH
CVSS 3.1
CVE-2026-20124
Cisco IOS XE Software SNMP Denial of Service Vulnerability
Overview
Description
A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to improper error handling when parsing SNMP requests. This vulnerability affects all versions of SNMP — Versions 1, 2c, and 3. An attacker could exploit this vulnerability by sending a malformed SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly. The attacker must have the SNMPv1 or v2c read-only or read-write community string or valid SNMPv3 user credentials on the affected device.
Details
INFO
Published Date :
Aug. 5, 2026, 5:16 p.m.
Last Modified :
Aug. 5, 2026, 6:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Impact
Affected Products
The following products are affected by CVE-2026-20124
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
Apply Cisco security advisories for SNMP-related vulnerabilities to prevent device reloads.
- Consult Cisco security advisories for affected SNMP versions.
- Update Cisco IOS XE Software to a fixed version.
- Restrict SNMP access to trusted hosts.
- Disable SNMP if not actively used.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-20124.
| URL | Resource |
|---|---|
| https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-snmp-dos-ZAqNm4MD |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-20124 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-20124
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-20124 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-20124 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 05, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-20124', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-05T17:20:40.573517Z'} -
New CVE Received by [email protected]
Aug. 05, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Cisco', 'product': 'Cisco IOS XE Software', 'versions': [{'status': 'affected', 'version': '17.2.1a'}, {'status': 'affected', 'version': '3.18.7SP'}, {'status': 'affected', 'version': '16.12.1y'}, {'status': 'affected', 'version': '16.12.3s'}, {'status': 'affected', 'version': '16.7.1b'}, {'status': 'affected', 'version': '16.6.2'}, {'status': 'affected', 'version': '16.6.5'}, {'status': 'affected', 'version': '16.12.1w'}, {'status': 'affected', 'version': '3.18.4S'}, {'status': 'affected', 'version': '16.9.1d'}, {'status': 'affected', 'version': '17.3.1'}, {'status': 'affected', 'version': '16.9.4c'}, {'status': 'affected', 'version': '16.7.1'}, {'status': 'affected', 'version': '17.2.1'}, {'status': 'affected', 'version': '16.6.8'}, {'status': 'affected', 'version': '16.9.1b'}, {'status': 'affected', 'version': '3.16.8S'}, {'status': 'affected', 'version': '16.9.2s'}, {'status': 'affected', 'version': '16.12.4'}, {'status': 'affected', 'version': '16.12.3a'}, {'status': 'affected', 'version': '17.1.1s'}, {'status': 'affected', 'version': '16.11.1a'}, {'status': 'affected', 'version': '16.7.2'}, {'status': 'affected', 'version': '16.11.1b'}, {'status': 'affected', 'version': '16.9.1s'}, {'status': 'affected', 'version': '16.9.3h'}, {'status': 'affected', 'version': '16.9.1c'}, {'status': 'affected', 'version': '16.6.5a'}, {'status': 'affected', 'version': '16.6.3'}, {'status': 'affected', 'version': '16.10.1f'}, {'status': 'affected', 'version': '17.2.1v'}, {'status': 'affected', 'version': '16.8.1e'}, {'status': 'affected', 'version': '16.9.3a'}, {'status': 'affected', 'version': '16.12.1a'}, {'status': 'affected', 'version': '16.12.1x'}, {'status': 'affected', 'version': '3.16.10aS'}, {'status': 'affected', 'version': '16.6.4s'}, {'status': 'affected', 'version': '16.10.1c'}, {'status': 'affected', 'version': '16.12.3'}, {'status': 'affected', 'version': '16.11.2'}, {'status': 'affected', 'version': '16.6.5b'}, {'status': 'affected', 'version': '16.12.2s'}, {'status': 'affected', 'version': '16.10.1b'}, {'status': 'affected', 'version': '16.7.3'}, {'status': 'affected', 'version': '16.6.7'}, {'status': 'affected', 'version': '16.9.6'}, {'status': 'affected', 'version': '16.9.2'}, {'status': 'affected', 'version': '3.16.10S'}, {'status': 'affected', 'version': '16.10.1'}, {'status': 'affected', 'version': '16.12.1t'}, {'status': 'affected', 'version': '3.18.3bSP'}, {'status': 'affected', 'version': '3.13.9S'}, {'status': 'affected', 'version': '3.18.3aSP'}, {'status': 'affected', 'version': '3.18.5SP'}, {'status': 'affected', 'version': '16.9.1'}, {'status': 'affected', 'version': '16.8.1a'}, {'status': 'affected', 'version': '3.18.8aSP'}, {'status': 'affected', 'version': '16.9.3s'}, {'status': 'affected', 'version': '16.6.7a'}, {'status': 'affected', 'version': '16.12.2'}, {'status': 'affected', 'version': '16.11.1'}, {'status': 'affected', 'version': '16.9.3'}, {'status': 'affected', 'version': '16.11.1s'}, {'status': 'affected', 'version': '16.12.1'}, {'status': 'affected', 'version': '3.16.9S'}, {'status': 'affected', 'version': '17.1.1'}, {'status': 'affected', 'version': '17.1.2'}, {'status': 'affected', 'version': '16.10.1d'}, {'status': 'affected', 'version': '17.1.1t'}, {'status': 'affected', 'version': '16.9.4'}, {'status': 'affected', 'version': '16.8.3'}, {'status': 'affected', 'version': '16.12.2t'}, {'status': 'affected', 'version': '16.9.5'}, {'status': 'affected', 'version': '3.16.7S'}, {'status': 'affected', 'version': '16.8.1s'}, {'status': 'affected', 'version': '16.10.1e'}, {'status': 'affected', 'version': '16.8.2'}, {'status': 'affected', 'version': '16.6.4'}, {'status': 'affected', 'version': '16.8.1b'}, {'status': 'affected', 'version': '16.10.1a'}, {'status': 'affected', 'version': '16.12.1z'}, {'status': 'affected', 'version': '16.8.1c'}, {'status': 'affected', 'version': '16.9.1a'}, {'status': 'affected', 'version': '3.16.7aS'}, {'status': 'affected', 'version': '16.9.5f'}, {'status': 'affected', 'version': '16.6.4a'}, {'status': 'affected', 'version': '16.10.1g'}, {'status': 'affected', 'version': '3.13.10S'}, {'status': 'affected', 'version': '16.8.1'}, {'status': 'affected', 'version': '16.6.6'}, {'status': 'affected', 'version': '16.9.2a'}, {'status': 'affected', 'version': '16.8.1d'}, {'status': 'affected', 'version': '16.10.3'}, {'status': 'affected', 'version': '3.18.4SP'}, {'status': 'affected', 'version': '3.18.6SP'}, {'status': 'affected', 'version': '3.18.3SP'}, {'status': 'affected', 'version': '16.7.1a'}, {'status': 'affected', 'version': '16.11.1c'}, {'status': 'affected', 'version': '16.10.1s'}, {'status': 'affected', 'version': '17.2.1r'}, {'status': 'affected', 'version': '3.16.7bS'}, {'status': 'affected', 'version': '17.1.1a'}, {'status': 'affected', 'version': '16.10.2'}, {'status': 'affected', 'version': '16.12.2a'}, {'status': 'affected', 'version': '3.16.6bS'}, {'status': 'affected', 'version': '16.12.1c'}, {'status': 'affected', 'version': '16.12.1s'}, {'status': 'affected', 'version': '16.7.4'}, {'status': 'affected', 'version': '3.18.9SP'}, {'status': 'affected', 'version': '17.2.2'}, {'status': 'affected', 'version': '16.9.8'}, {'status': 'affected', 'version': '16.9.7'}, {'status': 'affected', 'version': '17.1.3'}, {'status': 'affected', 'version': '17.3.1a'}, {'status': 'affected', 'version': '17.3.2a'}, {'status': 'affected', 'version': '16.12.5'}, {'status': 'affected', 'version': '17.3.1w'}, {'status': 'affected', 'version': '17.3.2'}, {'status': 'affected', 'version': '17.4.1'}, {'status': 'affected', 'version': '16.12.4a'}, {'status': 'affected', 'version': '17.4.1a'}, {'status': 'affected', 'version': '3.16.10bS'}, {'status': 'affected', 'version': '17.3.1x'}, {'status': 'affected', 'version': '17.3.3'}, {'status': 'affected', 'version': '16.6.9'}, {'status': 'affected', 'version': '17.2.3'}, {'status': 'affected', 'version': '17.5.1'}, {'status': 'affected', 'version': '16.12.1z1'}, {'status': 'affected', 'version': '16.12.5a'}, {'status': 'affected', 'version': '17.4.1b'}, {'status': 'affected', 'version': '17.3.1z'}, {'status': 'affected', 'version': '16.12.5b'}, {'status': 'affected', 'version': '17.4.2'}, {'status': 'affected', 'version': '17.3.3a'}, {'status': 'affected', 'version': '17.3.5'}, {'status': 'affected', 'version': '17.3.4'}, {'status': 'affected', 'version': '17.5.1a'}, {'status': 'affected', 'version': '16.12.6'}, {'status': 'affected', 'version': '17.6.1'}, {'status': 'affected', 'version': '16.12.1z2'}, {'status': 'affected', 'version': '16.6.10'}, {'status': 'affected', 'version': '17.3.4a'}, {'status': 'affected', 'version': '17.6.1a'}, {'status': 'affected', 'version': '17.7.1'}, {'status': 'affected', 'version': '17.6.1x'}, {'status': 'affected', 'version': '17.6.2'}, {'status': 'affected', 'version': '16.12.6a'}, {'status': 'affected', 'version': '17.3.4c'}, {'status': 'affected', 'version': '17.4.2a'}, {'status': 'affected', 'version': '17.3.4b'}, {'status': 'affected', 'version': '17.7.1a'}, {'status': 'affected', 'version': '16.12.7'}, {'status': 'affected', 'version': '17.8.1a'}, {'status': 'affected', 'version': '17.6.3a'}, {'status': 'affected', 'version': '17.6.3'}, {'status': 'affected', 'version': '17.7.2'}, {'status': 'affected', 'version': '17.7.1b'}, {'status': 'affected', 'version': '17.9.1w'}, {'status': 'affected', 'version': '17.3.5a'}, {'status': 'affected', 'version': '17.6.1z'}, {'status': 'affected', 'version': '16.12.8'}, {'status': 'affected', 'version': '17.8.1'}, {'status': 'affected', 'version': '17.9.1'}, {'status': 'affected', 'version': '17.6.4'}, {'status': 'affected', 'version': '17.3.5b'}, {'status': 'affected', 'version': '17.9.1a'}, {'status': 'affected', 'version': '17.3.6'}, {'status': 'affected', 'version': '17.10.1'}, {'status': 'affected', 'version': '16.9.8a'}, {'status': 'affected', 'version': '17.6.1z1'}, {'status': 'affected', 'version': '17.10.1a'}, {'status': 'affected', 'version': '17.9.2'}, {'status': 'affected', 'version': '17.6.5'}, {'status': 'affected', 'version': '17.9.1x'}, {'status': 'affected', 'version': '17.9.1y'}, {'status': 'affected', 'version': '16.9.8b'}, {'status': 'affected', 'version': '17.3.7'}, {'status': 'affected', 'version': '17.9.2a'}, {'status': 'affected', 'version': '17.9.3'}, {'status': 'affected', 'version': '16.12.9'}, {'status': 'affected', 'version': '17.11.1'}, {'status': 'affected', 'version': '17.10.1b'}, {'status': 'affected', 'version': '17.6.6'}, {'status': 'affected', 'version': '17.9.1x1'}, {'status': 'affected', 'version': '17.11.1a'}, {'status': 'affected', 'version': '17.9.3a'}, {'status': 'affected', 'version': '17.12.1'}, {'status': 'affected', 'version': '17.3.8'}, {'status': 'affected', 'version': '17.9.4'}, {'status': 'affected', 'version': '16.12.10'}, {'status': 'affected', 'version': '17.12.1w'}, {'status': 'affected', 'version': '17.9.1y1'}, {'status': 'affected', 'version': '17.12.1a'}, {'status': 'affected', 'version': '17.9.5'}, {'status': 'affected', 'version': '17.13.1'}, {'status': 'affected', 'version': '17.12.1x'}, {'status': 'affected', 'version': '17.12.2'}, {'status': 'affected', 'version': '17.14.1'}, {'status': 'affected', 'version': '17.9.4a'}, {'status': 'affected', 'version': '17.3.8a'}, {'status': 'affected', 'version': '17.6.6a'}, {'status': 'affected', 'version': '17.6.5a'}, {'status': 'affected', 'version': '17.6.7'}, {'status': 'affected', 'version': '16.12.10a'}, {'status': 'affected', 'version': '17.15.1'}, {'status': 'affected', 'version': '17.13.1a'}, {'status': 'affected', 'version': '17.12.2a'}, {'status': 'affected', 'version': '16.12.11'}, {'status': 'affected', 'version': '17.12.3'}, {'status': 'affected', 'version': '17.12.1y'}, {'status': 'affected', 'version': '17.12.1z'}, {'status': 'affected', 'version': '17.9.5a'}, {'status': 'affected', 'version': '17.14.1a'}, {'status': 'affected', 'version': '17.9.5b'}, {'status': 'affected', 'version': '17.6.8'}, {'status': 'affected', 'version': '16.12.12'}, {'status': 'affected', 'version': '17.12.4'}, {'status': 'affected', 'version': '17.9.6'}, {'status': 'affected', 'version': '17.17.1'}, {'status': 'affected', 'version': '17.16.1'}, {'status': 'affected', 'version': '17.15.1w'}, {'status': 'affected', 'version': '17.12.3a'}, {'status': 'affected', 'version': '17.9.5c'}, {'status': 'affected', 'version': '17.15.1a'}, {'status': 'affected', 'version': '17.12.1z1'}, {'status': 'affected', 'version': '17.15.2'}, {'status': 'affected', 'version': '17.15.1b'}, {'status': 'affected', 'version': '17.9.5d'}, {'status': 'affected', 'version': '17.15.1x'}, {'status': 'affected', 'version': '17.9.6a'}, {'status': 'affected', 'version': '17.12.1z2'}, {'status': 'affected', 'version': '17.6.8a'}, {'status': 'affected', 'version': '17.16.1a'}, {'status': 'affected', 'version': '16.12.13'}, {'status': 'affected', 'version': '17.15.3'}, {'status': 'affected', 'version': '17.9.7'}, {'status': 'affected', 'version': '17.12.5'}, {'status': 'affected', 'version': '17.15.1y'}, {'status': 'affected', 'version': '17.9.5e'}, {'status': 'affected', 'version': '17.12.4a'}, {'status': 'affected', 'version': '17.15.2a'}, {'status': 'affected', 'version': '17.15.2c'}, {'status': 'affected', 'version': '17.15.2b'}, {'status': 'affected', 'version': '17.12.1z3'}, {'status': 'affected', 'version': '17.9.5f'}, {'status': 'affected', 'version': '17.12.4b'}, {'status': 'affected', 'version': '17.12.5a'}, {'status': 'affected', 'version': '17.18.1'}, {'status': 'affected', 'version': '17.12.6'}, {'status': 'affected', 'version': '17.12.1z4'}, {'status': 'affected', 'version': '17.9.8'}, {'status': 'affected', 'version': '17.9.7a'}, {'status': 'affected', 'version': '17.15.3a'}, {'status': 'affected', 'version': '17.15.4'}, {'status': 'affected', 'version': '17.12.5b'}, {'status': 'affected', 'version': '17.15.3b'}, {'status': 'affected', 'version': '16.12.14'}, {'status': 'affected', 'version': '17.9.7b'}, {'status': 'affected', 'version': '17.12.5c'}, {'status': 'affected', 'version': '17.18.1a'}, {'status': 'affected', 'version': '17.15.4a'}, {'status': 'affected', 'version': '17.18.2'}, {'status': 'affected', 'version': '17.18.1w'}, {'status': 'affected', 'version': '17.15.4b'}, {'status': 'affected', 'version': '17.12.6a'}, {'status': 'affected', 'version': '17.15.4c'}, {'status': 'affected', 'version': '17.9.9'}, {'status': 'affected', 'version': '17.12.5d'}, {'status': 'affected', 'version': '16.12.15'}, {'status': 'affected', 'version': '17.15.4s1'}, {'status': 'affected', 'version': '17.12.1z5'}, {'status': 'affected', 'version': '17.18.1x'}, {'status': 'affected', 'version': '17.12.1z6'}, {'status': 'affected', 'version': '17.15.4d'}, {'status': 'affected', 'version': '17.12.6b'}, {'status': 'affected', 'version': '17.4.1c'}, {'status': 'affected', 'version': '17.18.1y'}], 'defaultStatus': 'unknown'}] Added Description A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to improper error handling when parsing SNMP requests. This vulnerability affects all versions of SNMP — Versions 1, 2c, and 3. An attacker could exploit this vulnerability by sending a malformed SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly. The attacker must have the SNMPv1 or v2c read-only or read-write community string or valid SNMPv3 user credentials on the affected device. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H Added CWE CWE-772 Added Reference https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-snmp-dos-ZAqNm4MD
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.