CVE-2026-20279: Cisco IOS XR Software Security Hardening Release: September 2026
- Is it exploited?
Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
- How likely is exploitation in the next 30 days?
- 0.5%
Up from 0.3% on .
EPSS score, percentile 42.1 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 9.8 Critical
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 6.5.29
- 7.0.1
- 6.5.26
- 6.5.25
- 6.5.28
- 6.5.90
and 6 more in the table below
Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
What to do
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | 6.5.29 |
| Affected | 7.0.1 |
| Affected | 6.5.26 |
| Affected | 6.5.25 |
| Affected | 6.5.28 |
| Affected | 6.5.90 |
| Affected | 7.1.1 |
| Affected | 7.0.90 |
| Affected | 6.7.1 |
| Affected | 7.0.2 |
| Affected | 7.1.15 |
| Affected | 7.2.1 |
Versions not listed are: unknown.
And 100 more version entries in the CVE record.
Source: CVE List, as of . About the data.
About this vulnerability
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-2026-20279 are related to improper access control issues that are…
Summary: CVE record, as of .
- CISA has not added CVE-2026-20279 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
- The CVE record was published on 2 Sep 2026.
- The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.5% (percentile 42.1), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
- CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact total.
Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.
Description
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-2026-20279 are related to improper access control issues that are grouped under the Common Weakness Enumeration (CWE) CWE-284.
Source: CVE List, as of . About the data.
Weakness
CWE-284
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| CVE record last updated |
References
1
Known exploited Cisco vulnerabilities
- CVE-2026-76418: Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
- CVE-2026-76519: Cisco Secure Email Gateway Relative Path Traversal Vulnerability
- CVE-2026-76504: Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability
- CVE-2026-76460: Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability
- CVE-2026-76461: Cisco Secure Email Gateway SQL Injection Vulnerability