Is CVE-2026-20276 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-20276 being exploited in the wild.

How severe is CVE-2026-20276?

High severity, with a CVSS score of 8.6, published 2 September 2026.

Which products and versions are affected?

Cisco IOS XR Software All releases including IOS XR7 (LNT).

Is there a fix for CVE-2026-20276?

A patch was published on 2026-09-02: Software updates released to address vulnerability Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-20276 attacked?

It is attacked over the network, in an operating system.

Am I affected by CVE-2026-20276?

Check whether you run Cisco IOS XR Software at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-20276: Cisco IOS XR Software control flow management vulnerability

CVE-2026-20276 · Severity: high · CVSS 8.6 · Published 2026-09-02

Cisco IOS XR is a network operating system used in core routing and network infrastructure devices. This vulnerability involves insufficient control flow management that allows an unauthenticated network attacker to cause denial of service, execute unauthorized code, or gain unauthorized access to sensitive data on affected routers and network appliances. The vulnerabilities were discovered during an internal security review and are part of a security hardening release covering multiple issues across the codebase.

Technologies: Cisco IOS XR Software. Vendors: Cisco.

Quick answers

Is CVE-2026-20276 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-20276 being exploited in the wild.
How severe is CVE-2026-20276?: High severity, with a CVSS score of 8.6, published 2 September 2026.
Which products and versions are affected?: Cisco IOS XR Software All releases including IOS XR7 (LNT).
Is there a fix for CVE-2026-20276?: A patch was published on 2026-09-02: Software updates released to address vulnerability Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-20276 attacked?: It is attacked over the network, in an operating system.
Am I affected by CVE-2026-20276?: Check whether you run Cisco IOS XR Software at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

CVE-2026-20276 is grouped under CWE-691 (Insufficient Control Flow Management) and represents one of seven vulnerability classes addressed in Cisco's security hardening release. The vulnerability affects all releases of Cisco IOS XR Software with a base CVSS score of 8.6 and no authentication or user interaction required for exploitation. The attack vector is network-based, allowing an unauthenticated attacker to trigger the vulnerability remotely. Cisco has released software updates to remediate this vulnerability; however, no workarounds are available, making patching mandatory for affected systems.

Affected products

Cisco IOS XR Software All releases including IOS XR7 (LNT)

Timeline

2026-09-02: disclosed: CVE-2026-20276 disclosed as part of security hardening release
2026-09-02: patched: Software updates released to address vulnerability

References

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