Cisco IOS XR protection mech. failure (CWE-693)
CVE-2026-20277 Published on September 2, 2026
Cisco IOS XR Software Security Hardening Release: September 2026
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-2026-20277 are related to protection mechanism failure issues that are grouped under the Common Weakness Enumeration (CWE) CWE-693.
Vulnerability Analysis
CVE-2026-20277 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and a high impact on availability.
Weakness Type
Protection Mechanism Failure
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product. This weakness covers three distinct situations. A "missing" protection mechanism occurs when the application does not define any mechanism against a certain class of attack. An "insufficient" protection mechanism might provide some defenses - for example, against the most common attacks - but it does not protect against everything that is intended. Finally, an "ignored" mechanism occurs when a mechanism is available and in active use within the product, but the developer has not applied it in some code path.
Products Associated with CVE-2026-20277
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Affected Versions
Cisco IOS XR Software:- Version 6.5.29 is affected.
- Version 7.0.1 is affected.
- Version 6.5.26 is affected.
- Version 6.5.25 is affected.
- Version 6.5.28 is affected.
- Version 6.5.90 is affected.
- Version 7.1.1 is affected.
- Version 7.0.90 is affected.
- Version 6.7.1 is affected.
- Version 7.0.2 is affected.
- Version 7.1.15 is affected.
- Version 7.2.1 is affected.
- Version 7.1.2 is affected.
- Version 6.7.2 is affected.
- Version 7.0.11 is affected.
- Version 7.0.12 is affected.
- Version 7.0.14 is affected.
- Version 7.1.25 is affected.
- Version 7.2.12 is affected.
- Version 7.3.1 is affected.
- Version 7.1.3 is affected.
- Version 6.7.3 is affected.
- Version 7.4.1 is affected.
- Version 7.2.2 is affected.
- Version 6.7.4 is affected.
- Version 6.5.31 is affected.
- Version 7.3.15 is affected.
- Version 7.3.16 is affected.
- Version 6.8.1 is affected.
- Version 7.4.15 is affected.
- Version 6.5.32 is affected.
- Version 7.3.2 is affected.
- Version 7.5.1 is affected.
- Version 7.4.16 is affected.
- Version 7.3.27 is affected.
- Version 7.6.1 is affected.
- Version 7.5.2 is affected.
- Version 7.8.1 is affected.
- Version 7.6.15 is affected.
- Version 7.5.12 is affected.
- Version 7.8.12 is affected.
- Version 7.3.3 is affected.
- Version 7.7.1 is affected.
- Version 6.8.2 is affected.
- Version 7.3.4 is affected.
- Version 7.4.2 is affected.
- Version 6.7.35 is affected.
- Version 6.9.1 is affected.
- Version 7.6.2 is affected.
- Version 7.5.3 is affected.
- Version 7.7.2 is affected.
- Version 6.9.2 is affected.
- Version 7.9.1 is affected.
- Version 7.10.1 is affected.
- Version 7.8.2 is affected.
- Version 7.5.4 is affected.
- Version 6.5.33 is affected.
- Version 7.8.22 is affected.
- Version 7.7.21 is affected.
- Version 7.9.2 is affected.
- Version 7.3.5 is affected.
- Version 7.5.5 is affected.
- Version 7.11.1 is affected.
- Version 7.9.21 is affected.
- Version 7.10.2 is affected.
- Version 24.1.1 is affected.
- Version 7.6.3 is affected.
- Version 7.3.6 is affected.
- Version 7.5.52 is affected.
- Version 7.11.2 is affected.
- Version 24.2.1 is affected.
- Version 24.1.2 is affected.
- Version 24.2.11 is affected.
- Version 24.3.1 is affected.
- Version 24.4.1 is affected.
- Version 24.2.2 is affected.
- Version 7.8.23 is affected.
- Version 7.11.21 is affected.
- Version 24.2.20 is affected.
- Version 24.3.2 is affected.
- Version 24.4.10 is affected.
- Version 6.5.35 is affected.
- Version 25.1.1 is affected.
- Version 24.4.2 is affected.
- Version 24.3.20 is affected.
- Version 24.4.15 is affected.
- Version 25.2.1 is affected.
- Version 6.5.351 is affected.
- Version 25.1.2 is affected.
- Version 24.3.30 is affected.
- Version 25.3.1 is affected.
- Version 6.5.352 is affected.
- Version 24.4.30 is affected.
- Version 24.2.21 is affected.
- Version 25.4.1 is affected.
- Version 25.2.2 is affected.
- Version 25.2.15 is affected.
- Version 7.2.0 is affected.
- Version 7.0.0 is affected.
- Version 25.2.30 is affected.
- Version 6.5.353 is affected.
- Version 26.1.1 is affected.
- Version 25.1.30 is affected.
- Version 25.3.15 is affected.
- Version 26.2.100 is affected.
- Version 25.4.2 is affected.
- Version 26.2.1 is affected.
- Version 25.4.30 is affected.
- Version 26.1.2 is affected.
- Version 25.4.201 is affected.
- Version 26.2.101 is affected.