Vulnerability · Published Sep 2, 2026 · Assigned by cisco
CVE-2026-20274Cisco IOS XR Software Security Hardening Release: September 2026
Critical 9.8
In plain English
A critical-severity security flaw in Cisco IOS XR Software from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).
Official description
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20274 are related to improper resource control issues that are grouped under the Common Weakness Enumeration (CWE) CWE-664.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Cisco | Cisco IOS XR Software | 6.5.297.0.16.5.266.5.256.5.286.5.907.1.17.0.90 |
Weakness: CWE-664 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H