Unauthenticated system compromise via access-control failures
Published Sep 2, 2026 · Updated Sep 3, 2026
Improper access control in Cisco IOS XR Software allows remote attackers to compromise confidentiality, integrity, and availability. The grouped record covers improper certificate validation, missing authentication for critical functions, missing authorization, and incorrect authorization across undisclosed components. Cisco assigns the maximum case a network-reachable, unauthenticated path with no user interaction, but it does not disclose the affected interfaces, resources, or per-defect consequences; all IOS XR releases, including IOS XR7, are in scope regardless of configuration.
Summary
What happened
Improper access control in Cisco IOS XR Software allows remote attackers to compromise confidentiality, integrity, and availability. The grouped record covers improper certificate validation, missing authentication for critical functions, missing authorization, and incorrect authorization across undisclosed components. Cisco assigns the maximum case a network-reachable, unauthenticated path with no user interaction, but it does not disclose the affected interfaces, resources, or per-defect consequences; all IOS XR releases, including IOS XR7, are in scope regardless of configuration.
The record
- CVE
- CVE-2026-20279
- Published
- Sep 2, 2026
- Updated
- Sep 3, 2026
- Vendor
- ClamAV
- Product
- Cisco IOS XR Software
- Classifications
- CWE-284
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 2, 2026CVE publishedPublication date reported by the CVE source.
- Sep 3, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=24.1.1
- Affected versionversion=24.1.2
- Affected versionversion=24.2.1
- Affected versionversion=24.2.11
- Affected versionversion=24.2.2
- Affected versionversion=24.2.20
- Affected versionversion=24.2.21
- Affected versionversion=24.3.1
- Affected versionversion=24.3.2
- Affected versionversion=24.3.20
- Affected versionversion=24.3.30
- Affected versionversion=24.4.1
- Affected versionversion=24.4.10
- Affected versionversion=24.4.15
- Affected versionversion=24.4.2
- Affected versionversion=24.4.30
- Affected versionversion=25.1.1
- Affected versionversion=25.1.2
- Affected versionversion=25.1.30
- Affected versionversion=25.2.1
- Affected versionversion=25.2.15
- Affected versionversion=25.2.2
- Affected versionversion=25.2.30
- Affected versionversion=25.3.1
- Affected versionversion=25.3.15
- Affected versionversion=25.4.1
- Affected versionversion=25.4.2
- Affected versionversion=25.4.201
- Affected versionversion=25.4.30
- Affected versionversion=26.1.1
- Affected versionversion=26.1.2
- Affected versionversion=26.2.1
- Affected versionversion=26.2.100
- Affected versionversion=26.2.101
- Affected versionversion=6.5.25
- Affected versionversion=6.5.26
- Affected versionversion=6.5.28
- Affected versionversion=6.5.29
- Affected versionversion=6.5.31
- Affected versionversion=6.5.32
- Affected versionversion=6.5.33
- Affected versionversion=6.5.35
- Affected versionversion=6.5.351
- Affected versionversion=6.5.352
- Affected versionversion=6.5.353
- Affected versionversion=6.5.90
- Affected versionversion=6.7.1
- Affected versionversion=6.7.2
- Affected versionversion=6.7.3
- Affected versionversion=6.7.35
- Affected versionversion=6.7.4
- Affected versionversion=6.8.1
- Affected versionversion=6.8.2
- Affected versionversion=6.9.1
- Affected versionversion=6.9.2
- Affected versionversion=7.0.0
- Affected versionversion=7.0.1
- Affected versionversion=7.0.11
- Affected versionversion=7.0.12
- Affected versionversion=7.0.14
- Affected versionversion=7.0.2
- Affected versionversion=7.0.90
- Affected versionversion=7.10.1
- Affected versionversion=7.10.2
- Affected versionversion=7.1.1
- Affected versionversion=7.11.1
- Affected versionversion=7.11.2
- Affected versionversion=7.11.21
- Affected versionversion=7.1.15
- Affected versionversion=7.1.2
- Affected versionversion=7.1.25
- Affected versionversion=7.1.3
- Affected versionversion=7.2.0
- Affected versionversion=7.2.1
- Affected versionversion=7.2.12
- Affected versionversion=7.2.2
- Affected versionversion=7.3.1
- Affected versionversion=7.3.15
- Affected versionversion=7.3.16
- Affected versionversion=7.3.2
- Affected versionversion=7.3.27
- Affected versionversion=7.3.3
- Affected versionversion=7.3.4
- Affected versionversion=7.3.5
- Affected versionversion=7.3.6
- Affected versionversion=7.4.1
- Affected versionversion=7.4.15
- Affected versionversion=7.4.16
- Affected versionversion=7.4.2
- Affected versionversion=7.5.1
- Affected versionversion=7.5.12
- Affected versionversion=7.5.2
- Affected versionversion=7.5.3
- Affected versionversion=7.5.4
- Affected versionversion=7.5.5
- Affected versionversion=7.5.52
- Affected versionversion=7.6.1
- Affected versionversion=7.6.15
- Affected versionversion=7.6.2
- Affected versionversion=7.6.3
- Affected versionversion=7.7.1
- Affected versionversion=7.7.2
- Affected versionversion=7.7.21
- Affected versionversion=7.8.1
- Affected versionversion=7.8.12
- Affected versionversion=7.8.2
- Affected versionversion=7.8.22
- Affected versionversion=7.8.23
- Affected versionversion=7.9.1
- Affected versionversion=7.9.2
- Affected versionversion=7.9.21
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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