8.2

CVE-2026-20277: cisco cisco ios xr software Protection Mechanism Failure

CVSS: 8.2v3.1HighAwaiting analysis
Published 02-09-2026Last modified 18-09-2026
Open JSON

Vulnerability summary

CVE-2026-20277 is a high (CVSS 8.2) Protection Mechanism Failure vulnerability in cisco cisco ios xr software. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.3% of scored vulnerabilities.

Overall risk
33/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.2/10
010
High · v3.1 (CVE.org)
EPSS score
0.23%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 02-09-2026
    PublishedVulnerability first disclosed.
  2. 18-09-2026
    Last modifiedVulnerability information updated.

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-2026-20277 are related to protection mechanism failure issues that are grouped under the Common Weakness Enumeration (CWE) CWE-693.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

0.00 pp

From 0.23% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.23%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cisco1 product
  • cisco ios xr software6.5.29 | 7.0.1 | 6.5.26 | 6.5.25 | 6.5.28 | 6.5.90 | 7.1.1 | 7.0.90 | 6.7.1 | 7.0.2 | 7.1.15 | 7.2.1 | 7.1.2 | 6.7.2 | 7.0.11 | 7.0.12 | 7.0.14 | 7.1.25 | 7.2.12 | 7.3.1 | 7.1.3 | 6.7.3 | 7.4.1 | 7.2.2 | 6.7.4 | 6.5.31 | 7.3.15 | 7.3.16 | 6.8.1 | 7.4.15 | 6.5.32 | 7.3.2 | 7.5.1 | 7.4.16 | 7.3.27 | 7.6.1 | 7.5.2 | 7.8.1 | 7.6.15 | 7.5.12 | 7.8.12 | 7.3.3 | 7.7.1 | 6.8.2 | 7.3.4 | 7.4.2 | 6.7.35 | 6.9.1 | 7.6.2 | 7.5.3 | 7.7.2 | 6.9.2 | 7.9.1 | 7.10.1 | 7.8.2 | 7.5.4 | 6.5.33 | 7.8.22 | 7.7.21 | 7.9.2 | 7.3.5 | 7.5.5 | 7.11.1 | 7.9.21 | 7.10.2 | 24.1.1 | 7.6.3 | 7.3.6 | 7.5.52 | 7.11.2 | 24.2.1 | 24.1.2 | 24.2.11 | 24.3.1 | 24.4.1 | 24.2.2 | 7.8.23 | 7.11.21 | 24.2.20 | 24.3.2 | 24.4.10 | 6.5.35 | 25.1.1 | 24.4.2 | 24.3.20 | 24.4.15 | 25.2.1 | 6.5.351 | 25.1.2 | 24.3.30 | 25.3.1 | 6.5.352 | 24.4.30 | 24.2.21 | 25.4.1 | 25.2.2 | 25.2.15 | 7.2.0 | 7.0.0 | 25.2.30 | 6.5.353 | 26.1.1 | 25.1.30 | 25.3.15 | 26.2.100 | 25.4.2 | 26.2.1 | 25.4.30 | 26.1.2 | 25.4.201 | 26.2.101 | 25.2.21

1 vendor · 1 product

References

2 links