CVE-2026-20301
HIGHCVSS 8.6/10EPSS 0.33%
Last modified
CVE-2026-20301 is a high-severity vulnerability rated 8.6/10 on the CVSS scale. A vulnerability in the Extensible Messaging Client Protocol (XMCP), also referred to as the External Client protocol, of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of malformed XMCP packets. An attacker could exploit this vulnerability by sending a malformed XMCP packet to an affected device. EPSS estimates a 0.33% chance of exploitation in the next 30 days.
Description
A vulnerability in the Extensible Messaging Client Protocol (XMCP), also referred to as the External Client protocol, of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of malformed XMCP packets. An attacker could exploit this vulnerability by sending a malformed XMCP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload unexpectedly, resulting in a DoS condition. The attacker does not need the XMCP client username to exploit this vulnerability.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco IOS XE Software | 17.2.1a; 16.12.1y; 16.12.3s; 16.7.1b; 16.6.2; 16.6.5; 16.12.1w; 16.9.1d; 17.3.1; 16.9.4c; 16.7.1; 17.2.1; 16.6.8; 16.9.1b; 16.9.2s; 16.12.4; 16.12.3a; 17.1.1s; 16.11.1a; 16.7.2; 16.11.1b; 16.9.1s; 16.9.3h; 16.9.1c; 16.6.5a; 16.6.3; 16.10.1f; 17.2.1v; 16.8.1e; 16.9.3a; 16.12.1a; 16.12.1x; 3.16.10aS; 16.6.4s; 16.10.1c; 16.12.3; 16.11.2; 16.6.5b; 16.12.2s; 16.10.1b; 16.7.3; 16.6.7; 16.9.6; 16.9.2; 16.10.1; 16.12.1t; 16.9.1; 16.8.1a; 3.18.8aSP; 16.9.3s; 16.6.7a; 16.12.2; 16.11.1; 16.9.3; 16.11.1s; 16.12.1; 17.1.1; 17.1.2; 16.10.1d; 17.1.1t; 16.9.4; 16.8.3; 16.12.2t; 16.9.5; 16.8.1s; 16.10.1e; 16.8.2; 16.6.4; 16.8.1b; 16.10.1a; 16.12.1z; 16.8.1c; 16.9.1a; 16.9.5f; 16.6.4a; 16.10.1g; 16.8.1; 16.6.6; 16.9.2a; 16.8.1d; 16.10.3; 16.7.1a; 16.11.1c; 16.10.1s; 17.2.1r; 17.1.1a; 16.10.2; 16.12.2a; 16.12.1c; 16.12.1s; 16.7.4; 3.18.9SP; 17.2.2; 3.11.3E; 16.9.8; 16.9.7; 17.1.3; 17.3.1a; 3.11.4E; 17.3.2a; 16.12.5; 17.3.1w; 17.3.2; 3.11.3aE; 17.4.1; 16.12.4a; 17.4.1a; 3.16.10bS; 17.3.1x; 17.3.3; 16.6.9; 17.2.3; 17.5.1; 16.12.1z1; 16.12.5a; 17.4.1b; 17.3.1z; 16.12.5b; 17.4.2; 17.3.3a; 3.11.5E; 17.3.5; 17.3.4; 17.5.1a; 16.12.6; 17.6.1; 16.12.1z2; 16.6.10; 17.3.4a; 17.6.1a; 3.8.10cE; 17.7.1; 17.6.1x; 17.6.2; 16.12.6a; 17.3.4c; 17.4.2a; 17.3.4b; 17.7.1a; 16.12.7; 17.8.1a; 17.6.3a; 17.6.3; 17.7.2; 17.7.1b; 17.9.1w; 17.3.5a; 17.6.1z; 3.8.10dE; 16.12.8; 17.8.1; 17.9.1; 3.11.6E; 17.6.4; 3.11.7E; 17.3.5b; 17.9.1a; 17.3.6; 17.10.1; 3.11.8E; 16.9.8a; 17.6.1z1; 17.10.1a; 17.9.2; 17.6.5; 17.9.1x; 17.9.1y; 16.9.8b; 17.3.7; 17.9.2a; 17.9.3; 16.12.9; 17.11.1; 17.10.1b; 17.6.6; 17.9.1x1; 17.11.1a; 17.9.3a; 17.12.1; 17.3.8; 17.9.4; 16.12.10; 17.12.1w; 17.9.1y1; 17.12.1a; 3.11.9E; 17.9.5; 17.13.1; 17.12.1x; 17.12.2; 17.14.1; 17.9.4a; 17.3.8a; 17.6.6a; 17.6.5a; 17.6.7; 16.12.10a; 17.15.1; 17.13.1a; 17.12.2a; 16.12.11; 17.12.3; 17.12.1y; 3.11.10E; 17.12.1z; 17.9.5a; 17.14.1a; 17.9.5b; 17.6.8; 16.12.12; 17.12.4; 17.9.6; 17.17.1; 17.16.1; 17.15.1w; 17.12.3a; 3.11.11E; 17.9.5c; 17.15.1a; 17.12.1z1; 17.15.2; 17.15.1b; 17.9.5d; 17.15.1x; 17.9.6a; 17.12.1z2; 17.6.8a; 17.16.1a; 16.12.13; 17.15.3; 17.9.7; 17.12.5; 17.15.1y; 17.9.5e; 17.12.4a; 17.15.2a; 17.15.2c; 17.15.2b; 17.12.1z3; 17.9.5f; 17.12.4b; 3.11.12E; 17.12.5a; 17.18.1; 17.12.6; 17.12.1z4; 17.9.8; 17.9.7a; 17.15.3a; 17.15.4; 3.11.13E; 17.12.5b; 17.15.3b; 16.12.14; 17.18.1z; 17.9.7b; 17.12.5c; 26.1.1; 17.18.1a; 17.15.4a; 17.18.2; 17.18.1w; 17.15.4b; 17.12.6a; 17.12.7; 17.15.4c; 17.9.9; 17.12.5d; 16.12.15; 17.15.4s1; 17.15.5; 17.12.1z5; 17.18.1x; 17.12.1z6; 17.15.4d; 17.12.6b; 17.4.1c; 3.11.14E; 17.15.5a; 17.18.1y; 17.12.7a; 17.18.3; 17.12.7b; 17.18.3a; 26.1.1a; 26.2.1ea; 16.12.16 |
| Cisco | IOS | 15.2(7)E7; 15.2(8)E3; 15.7(3)M10; 15.8(3)M9; 15.9(3)M7; 15.2(7)E8; 15.2(8)E4; 15.9(3)M7a; 15.2(2)E10c; 15.2(4)E10d; 15.9(3)M6a; 15.9(3)M6b; 15.5(1)SY10; 15.5(1)SY11; 15.2(6)E1a; 15.4(1)SY4; 15.5(1)SY1; 15.2(2)E8; 15.2(6)E1; 15.7(3)M2; 15.2(4)E6; 15.2(1)SY6; 15.2(4)EA7; 15.2(6)E1s; 15.7(3)M3; 15.8(3)M; 15.2(1)SY7; 15.2(4)EA8; 15.8(3)M0a; 15.2(2)E9; 15.2(6)E2; 15.5(1)SY2; 15.2(4)E7; 15.2(6)E2a; 15.2(2)E9a; 15.8(3)M0b; 15.2(6)E2b; 15.8(3)M1; 15.8(3)M1a; 15.7(3)M4; 15.2(1)SY8; 15.2(4)E8; 15.5(1)SY3; 15.2(7)E; 15.7(3)M4a; 15.8(3)M2; 15.2(7)E0a; 15.8(3)M2a; 15.7(3)M4b; 15.2(2)E10; 15.2(7)E0s; 15.2(4)EA9; 15.2(7)E0b; 15.2(6)E3; 15.9(3)M; 15.8(3)M3; 15.5(1)SY4; 15.7(3)M5; 15.2(2)E10a; 15.2(4)E9; 15.2(7)E1; 15.8(3)M3b; 15.9(3)M0a; 15.2(7)E1a; 15.2(4)E10; 15.5(1)SY5; 15.2(4)EA9a; 15.9(3)M1; 15.8(3)M4; 15.7(3)M6; 15.2(7)E2; 15.5(1)SY6; 15.2(7)E3; 15.8(3)M5; 15.7(3)M7; 15.9(3)M2; 15.2(7)E2b; 15.9(3)M2a; 15.2(4)E10a; 15.2(7)E4; 15.5(1)SY7; 15.2(4)E10b; 15.2(7)E3k; 15.2(8)E; 15.9(3)M3; 15.8(3)M6; 15.7(3)M8; 15.8(3)M7; 15.5(1)SY8; 15.2(7)E5; 15.2(8)E1; 15.9(3)M4; 15.2(8)E2; 15.2(4)E10c; 15.7(3)M9; 15.2(2)E10b; 15.2(7)E6; 15.9(3)M4a; 15.5(1)SY9; 15.9(3)M5; 15.8(3)M8; 15.9(3)M6; 15.9(3)M9; 15.5(1)SY13; 15.9(3)M8b; 15.2(7)E9; 15.5(1)SY12; 15.7(3)M10a; 15.9(3)M8; 15.9(3)M8a; 15.2(8)E5; 15.2(7)E10; 15.7(3)M10b; 15.9(3)M3a; 15.8(3)M3a; 15.9(3)M3b; 15.6(2)SP7; 15.6(2)SP5; 15.6(2)SP8; 15.6(2)SP6; 15.6(2)SP4; 15.6(2)SP9; 15.6(2)SP8a; 15.9(3)M9a; 15.2(8)E6; 15.9(3)M10; 15.2(7)E11; 15.5(1)SY14; 15.2(8)E7; 15.2(4)E10e; 15.9(3)M11; 15.2(7)E12; 15.5(1)SY15; 15.2(8)E8; 15.5(1)SY16; 15.2(7)E13; 15.9(3)M12; 15.5(1)SY17; 15.2(7)E14; 15.9(3)M13 |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-20301?
A vulnerability in the Extensible Messaging Client Protocol (XMCP), also referred to as the External Client protocol, of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.
This vulnerability is due to improper handling of malformed XMCP packets. An attacker could exploit this vulnerability by sending a malformed XMCP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload unexpectedly, resulting in a DoS condition. The attacker does not need the XMCP client username to exploit this vulnerability.
How severe is CVE-2026-20301?
CVE-2026-20301 has a CVSS score of 8.6/10 (HIGH severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.
How do I fix CVE-2026-20301?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-2029The Livemesh Addons for Beaver Builder plugin for WordPress …6.4
- CVE-2026-20294A vulnerability in the web-based management interface of Cis…6.5
- CVE-2026-20296In Splunk Enterprise versions below 10.4.1, 10.2.5, 10.0.8, …8.3
- CVE-2026-20297In Splunk Enterprise versions below 10.4.1, 10.2.5, 10.0.8, …7.2
- CVE-2026-20298In Splunk Enterprise versions below 10.4.1, 10.2.5, 10.0.8, …6.5
- CVE-2026-2030The WPBakery Page Builder Addons by Livemesh plugin for Word…6.4
- CVE-2026-20303As part of Cisco's ongoing commitment to proactive security …9.9
- CVE-2026-20304As part of Cisco's ongoing commitment to proactive security …9.9
- CVE-2026-20308A vulnerability in the web-based management interface of Cis…4.3
- CVE-2026-2031An Improper Access Control vulnerability in several internal…10
- CVE-2026-20310As part of Cisco's ongoing commitment to proactive security …9.1
- CVE-2026-20311A vulnerability in the web-based management interface of Cis…6.3
Are you affected by CVE-2026-20301?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST