Cisco IOS XR Software Security Hardening Release: September 2026

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 software hardening releases that address multiple internally discovered vulnerabilities. These vulnerabilities were found during internal testing and are not known to be actively exploited. To assist customers in patching and streamline the disclosure process, Cisco has grouped these issues by their underlying vulnerability class — Common Weakness Enumeration (CWE) — and assigned a single Common Vulnerabilities and Exposures identifier (CVE ID) to each CWE grouping. Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-iosxr-qg64NcM Security Impact Rating: Critical CVE: CVE-2026-20274,CVE-2026-20275,CVE-2026-20276,CVE-2026-20277,CVE-2026-20278,CVE-2026-20279,CVE-2026-20280

What to do

Install the fixed versions listed in the official advisory. If you cannot update right away, apply the workarounds or mitigations it describes and limit access to the affected service.

Details

Vendor

Cisco

Product

Cisco IOS XR

CVE

CVE-2026-20274, CVE-2026-20275, CVE-2026-20276, CVE-2026-20277, CVE-2026-20278, CVE-2026-20279, CVE-2026-20280

Affected versions

Cisco IOS XR Software 6.5: 12 versions, from 6.5.25 to 6.5.353
Cisco IOS XR Software 7.0: 7 versions, from 7.0.0 to 7.0.90
Cisco IOS XR Software 7.1: 5 versions, from 7.1.1 to 7.1.25
Cisco IOS XR Software 6.7: 5 versions, from 6.7.1 to 6.7.35
Cisco IOS XR Software 7.2: 4 versions, from 7.2.0 to 7.2.12
Cisco IOS XR Software 7.3: 9 versions, from 7.3.1 to 7.3.27
Cisco IOS XR Software 7.4: 4 versions, from 7.4.1 to 7.4.16
Cisco IOS XR Software 6.8: 6.8.1; 6.8.2
Cisco IOS XR Software 7.5: 7 versions, from 7.5.1 to 7.5.52
Cisco IOS XR Software 7.6: 4 versions, from 7.6.1 to 7.6.15
Cisco IOS XR Software 7.8: 5 versions, from 7.8.1 to 7.8.23
Cisco IOS XR Software 7.7: 7.7.1; 7.7.2; 7.7.21
Cisco IOS XR Software 6.9: 6.9.1; 6.9.2
Cisco IOS XR Software 7.9: 7.9.1; 7.9.2; 7.9.21
Cisco IOS XR Software 7.10: 7.10.1; 7.10.2
Cisco IOS XR Software 7.11: 7.11.1; 7.11.2; 7.11.21
Cisco IOS XR Software 24.1: 24.1.1; 24.1.2
Cisco IOS XR Software 24.2: 5 versions, from 24.2.1 to 24.2.21
Cisco IOS XR Software 24.3: 4 versions, from 24.3.1 to 24.3.30
Cisco IOS XR Software 24.4: 5 versions, from 24.4.1 to 24.4.30
Cisco IOS XR Software 25.1: 25.1.1; 25.1.2; 25.1.30
Cisco IOS XR Software 25.2: 5 versions, from 25.2.1 to 25.2.30
Cisco IOS XR Software 25.3: 25.3.1; 25.3.15
Cisco IOS XR Software 25.4: 4 versions, from 25.4.1 to 25.4.201
Cisco IOS XR Software 26.1: 26.1.1; 26.1.2
Cisco IOS XR Software 26.2: 26.2.1; 26.2.100; 26.2.101 (from the advisory and NVD; check the exact builds in the official advisory)

CVSS score

9.8

Actively exploited

Not known at this time

Source

Cisco PSIRT – original advisory

Published

September 17, 2026

The description and the recommended action are quoted from the public advisory (the action is our generic advice); severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.