CVE-2026-20074

HIGHPre-NVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

Score 7.4 from GitHub Security Advisory (severity: HIGH) published 2026-03-11. a secondary CVSS source baseline 7.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
Trending — 4 sources updated this week
7.4
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.4Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly. This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and must have formed an adjacency.  

CVSS v3
7.4
EG Score
7.4(medium)
EPSS
5.6%
KEV
Not listed

Published

March 11, 2026

Last Modified

July 8, 2026

Advisory Details (1)

Auto-updated Jul 8, 2026
No patch confirmed yet.
generic

Cisco IOS XR Software Multi-Instance Intermediate System-to-Intermediate System Denial of Service Vulnerability

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-dos-kDMxpSzK

Vendor Advisories for CVE-2026-20074(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 5× in last 7d / 5× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 19:14 UTCEG score recompute
  4. 2026-07-08 19:14 UTCGHSA enrichment
  5. 2026-07-08 19:14 UTCNVD updatefirst tracked

Frequently asked(5)

What is CVE-2026-20074?
CVE-2026-20074 is a high vulnerability published on March 11, 2026. A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly. This vulnerability is due to insufficient input validation of…
When was CVE-2026-20074 disclosed?
CVE-2026-20074 was first published in the National Vulnerability Database on March 11, 2026, with the most recent update on July 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-20074 actively exploited?
CVE-2026-20074 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 5.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-20074?
CVE-2026-20074 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2026-20074?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20074, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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