8.6
High
CVE-2026-20301 A vulnerability in the Extensible Messaging Client Protocol (XMCP), also referred to as the External Client protocol, of…
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Cisco IOS XE Software | 26.2.1ea | No fix stated |
| Cisco IOS XE Software 26.1 | 26.1.1a → 26.1.1 | No fix stated |
| Cisco IOS XE Software 17.18 | 17.18.1z → 17.18.3 | No fix stated |
| Cisco IOS XE Software | 17.17.1 | No fix stated |
| Cisco IOS XE Software 17.16 | 17.16.1a → 17.16.1 | No fix stated |
| Cisco IOS XE Software 17.15 | 17.15.1w → 17.15.5 | No fix stated |
| Cisco IOS XE Software 17.14 | 17.14.1a → 17.14.1 | No fix stated |
| Cisco IOS XE Software 17.13 | 17.13.1a → 17.13.1 | No fix stated |
| Cisco IOS XE Software 17.12 | 17.12.1w → 17.12.7 | No fix stated |
Show the 23 other branches Hide the 23 other branches
| Product | Affected versions | Fixed in |
|---|---|---|
| Cisco IOS XE Software 17.11 | 17.11.1a → 17.11.1 | No fix stated |
| Cisco IOS XE Software 17.10 | 17.10.1a → 17.10.1 | No fix stated |
| Cisco IOS XE Software 17.9 | 17.9.1w → 17.9.9 | No fix stated |
| Cisco IOS XE Software 17.8 | 17.8.1a → 17.8.1 | No fix stated |
| Cisco IOS XE Software 17.7 | 17.7.1a → 17.7.2 | No fix stated |
| Cisco IOS XE Software 17.6 | 17.6.1x → 17.6.8 | No fix stated |
| Cisco IOS XE Software 17.5 | 17.5.1a → 17.5.1 | No fix stated |
| Cisco IOS XE Software 17.4 | 17.4.1c → 17.4.2 | No fix stated |
| Cisco IOS XE Software 17.3 | 17.3.1w → 17.3.8 | No fix stated |
| Cisco IOS XE Software 17.2 | 17.2.1v → 17.2.3 | No fix stated |
| Cisco IOS XE Software 17.1 | 17.1.1s → 17.1.3 | No fix stated |
| Cisco IOS XE Software 16.12 | 16.12.1y → 16.12.16 | No fix stated |
| Cisco IOS XE Software 16.11 | 16.11.1s → 16.11.2 | No fix stated |
| Cisco IOS XE Software 16.10 | 16.10.1f → 16.10.3 | No fix stated |
| Cisco IOS XE Software 16.9 | 16.9.1d → 16.9.8 | No fix stated |
| Cisco IOS XE Software 16.8 | 16.8.1e → 16.8.3 | No fix stated |
| Cisco IOS XE Software 16.7 | 16.7.1a → 16.7.4 | No fix stated |
| Cisco IOS XE Software 16.6 | 16.6.2 → 16.6.10 | No fix stated |
| Cisco IOS XE Software 3.18 | 3.18.8aSP → 3.18.9SP | No fix stated |
| Cisco IOS XE Software 3.16 | 3.16.10aS → 3.16.10bS | No fix stated |
| Cisco IOS XE Software 3.11 | 3.11.3E → 3.11.14E | No fix stated |
| Cisco IOS XE Software | 3.8.10cE | No fix stated |
| IOS | Versions not published |
References
- cisco-sa-ios-xmcp-thbAr34t sec.cloudapps.cisco.com
Timeline
- Published
- Last modified
Other CVEs of Cisco IOS XE Software
The 248 CVEs of Cisco IOS XE Software →
CVE-2026-20311
A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote…
6.3
Medium
CVE-2026-20308
A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote…
4.3
Medium
CVE-2026-20273
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering…
8.6
High
CVE-2026-20272
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering…
9.8
Critical