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CVE-2026-20274

Cisco IOS XR Software Security Hardening Release: September 2026

No known exploitation. EPSS puts it in the 45th percentile. A vendor fix is available.

CVSS 3.19.8CriticalEPSS percentile45th0.5% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFixVendor fixNo build named by the sources

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

The vendor has published a fix. Version details are below where the sources state them.

  • Cisco IOS XR SoftwareAffected: 6.5.29Upgrade to: not statedAffected: 7.0.1Upgrade to: not statedAffected: 6.5.26Upgrade to: not statedAffected: 6.5.25Upgrade to: not stated + 108 more branchesStated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

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-2026-20274 are related to improper resource control issues that are grouped under the Common Weakness Enumeration (CWE) CWE-664.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS45th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.5% chance of exploitation activity in the next 30 days, which ranks it in the 45th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

11 events over 15 days, from the signal feeds we watch.

  1. Patch availablerecord updated
  2. Record updated
  3. OpenVAS check added
  4. Record updated
  5. Record updated
  6. Publishedpublished, weakness classified, weakness classified, record updated

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Scored 9.8 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

Sources

References in the record

In the news

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We'll flag the next CVE, public exploit or patch for Ios Xr, not every advisory.