Answer in brief
CVE-2026-20311 records a Medium severity (CVSS 6.3) vulnerability in Cisco IOS XE Software Web UI Denial of Service Vulnerability. The current sources do not mark it as known exploited. The current feed maps Cisco/Cisco IOS XE Software (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Cisco/Cisco IOS XE Software (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Cisco/Cisco IOS XE Softwaregeneric | 17.3.1 || 17.3.1a || 17.3.2a || 17.3.1w || 17.3.2 || 17.4.1 || 17.4.1a || 17.3.1x || 17.3.3 || 17.5.1 || 17.4.1b || 17.3.1z || 17.4.2 || 17.3.3a || 17.3.5 || 17.3.4 || 17.5.1a || 17.6.1 || 17.3.4a || 17.6.1a || 17.7.1 || 17.6.1x || 17.6.2 || 17.3.4c || 17.4.2a || 17.3.4b || 17.7.1a || 17.8.1a || 17.6.3a || 17.6.3 || 17.7.2 || 17.7.1b || 17.9.1w || 17.3.5a || 17.6.1z || 17.8.1 || 17.9.1 || 17.6.4 || 17.3.5b || 17.9.1a || 17.3.6 || 17.10.1 || 17.6.1z1 || 17.10.1a || 17.9.2 || 17.6.5 || 17.9.1x || 17.9.1y || 17.3.7 || 17.9.2a || 17.9.3 || 17.11.1 || 17.10.1b || 17.6.6 || 17.9.1x1 || 17.11.1a || 17.9.3a || 17.12.1 || 17.3.8 || 17.9.4 || 17.12.1w || 17.9.1y1 || 17.12.1a || 17.9.5 || 17.13.1 || 17.12.1x || 17.12.2 || 17.14.1 || 17.9.4a || 17.3.8a || 17.6.6a || 17.6.5a || 17.6.7 || 17.15.1 || 17.13.1a || 17.12.2a || 17.12.3 || 17.12.1y || 17.12.1z || 17.9.5a || 17.14.1a || 17.9.5b || 17.6.8 || 17.12.4 || 17.9.6 || 17.17.1 || 17.16.1 || 17.15.1w || 17.12.3a || 17.9.5c || 17.15.1a || 17.12.1z1 || 17.15.2 || 17.15.1b || 17.9.5d || 17.15.1x || 17.9.6a || 17.12.1z2 || 17.6.8a || 17.16.1a || 17.15.3 || 17.9.7 || 17.12.5 || 17.15.1y || 17.9.5e || 17.12.4a || 17.15.2a || 17.15.2c || 17.15.2b || 17.12.1z3 || 17.9.5f || 17.12.4b || 17.12.5a || 17.18.1 || 17.12.6 || 17.12.1z4 || 17.9.8 || 17.9.7a || 17.15.3a || 17.15.4 || 17.12.5b || 17.15.3b || 17.18.1z || 17.9.7b || 17.12.5c || 26.1.1 || 17.18.1a || 17.15.4a || 17.18.2 || 17.18.1w || 17.15.4b || 17.12.6a || 17.12.7 || 17.15.4c || 17.9.9 || 17.12.5d || 17.15.4s1 || 17.15.5 || 17.12.1z5 || 17.18.1x || 17.12.1z6 || 17.15.4d || 17.12.6b || 17.4.1c || 17.15.5a || 17.18.1y || 17.12.7a || 17.18.3 || 17.12.7b || 17.18.3a || 26.1.1a || 26.2.1ea | Not reported |
Published upstream
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient error handling in the web-based management interface. An attacker could exploit this vulnerability by authenticating with a malformed certificate. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-20311 records a Medium severity (CVSS 6.3) vulnerability in Cisco IOS XE Software Web UI Denial of Service Vulnerability. The current sources do not mark it as known exploited. The current feed maps Cisco/Cisco IOS XE Software (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Cisco/Cisco IOS XE Software (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Cisco/Cisco IOS XE Softwaregeneric | 17.3.1 || 17.3.1a || 17.3.2a || 17.3.1w || 17.3.2 || 17.4.1 || 17.4.1a || 17.3.1x || 17.3.3 || 17.5.1 || 17.4.1b || 17.3.1z || 17.4.2 || 17.3.3a || 17.3.5 || 17.3.4 || 17.5.1a || 17.6.1 || 17.3.4a || 17.6.1a || 17.7.1 || 17.6.1x || 17.6.2 || 17.3.4c || 17.4.2a || 17.3.4b || 17.7.1a || 17.8.1a || 17.6.3a || 17.6.3 || 17.7.2 || 17.7.1b || 17.9.1w || 17.3.5a || 17.6.1z || 17.8.1 || 17.9.1 || 17.6.4 || 17.3.5b || 17.9.1a || 17.3.6 || 17.10.1 || 17.6.1z1 || 17.10.1a || 17.9.2 || 17.6.5 || 17.9.1x || 17.9.1y || 17.3.7 || 17.9.2a || 17.9.3 || 17.11.1 || 17.10.1b || 17.6.6 || 17.9.1x1 || 17.11.1a || 17.9.3a || 17.12.1 || 17.3.8 || 17.9.4 || 17.12.1w || 17.9.1y1 || 17.12.1a || 17.9.5 || 17.13.1 || 17.12.1x || 17.12.2 || 17.14.1 || 17.9.4a || 17.3.8a || 17.6.6a || 17.6.5a || 17.6.7 || 17.15.1 || 17.13.1a || 17.12.2a || 17.12.3 || 17.12.1y || 17.12.1z || 17.9.5a || 17.14.1a || 17.9.5b || 17.6.8 || 17.12.4 || 17.9.6 || 17.17.1 || 17.16.1 || 17.15.1w || 17.12.3a || 17.9.5c || 17.15.1a || 17.12.1z1 || 17.15.2 || 17.15.1b || 17.9.5d || 17.15.1x || 17.9.6a || 17.12.1z2 || 17.6.8a || 17.16.1a || 17.15.3 || 17.9.7 || 17.12.5 || 17.15.1y || 17.9.5e || 17.12.4a || 17.15.2a || 17.15.2c || 17.15.2b || 17.12.1z3 || 17.9.5f || 17.12.4b || 17.12.5a || 17.18.1 || 17.12.6 || 17.12.1z4 || 17.9.8 || 17.9.7a || 17.15.3a || 17.15.4 || 17.12.5b || 17.15.3b || 17.18.1z || 17.9.7b || 17.12.5c || 26.1.1 || 17.18.1a || 17.15.4a || 17.18.2 || 17.18.1w || 17.15.4b || 17.12.6a || 17.12.7 || 17.15.4c || 17.9.9 || 17.12.5d || 17.15.4s1 || 17.15.5 || 17.12.1z5 || 17.18.1x || 17.12.1z6 || 17.15.4d || 17.12.6b || 17.4.1c || 17.15.5a || 17.18.1y || 17.12.7a || 17.18.3 || 17.12.7b || 17.18.3a || 26.1.1a || 26.2.1ea | Not reported |
Published upstream
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient error handling in the web-based management interface. An attacker could exploit this vulnerability by authenticating with a malformed certificate. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.
Quoted source text, attributed separately from HOL analysis.