Is CVE-2026-20273 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-20273 being exploited in the wild.

How severe is CVE-2026-20273?

High severity, with a CVSS score of 8.6, published 5 August 2026.

Which products and versions are affected?

Cisco IOS XE 17.9, 17.12, 17.15, 17.18, 26.1.

Is there a fix for CVE-2026-20273?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-20273 attacked?

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

Am I affected by CVE-2026-20273?

Check whether you run Cisco IOS XE 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-2026-20273: Cisco IOS XE Software improper input validation

CVE-2026-20273 · Severity: high · CVSS 8.6 · Published 2026-08-05

Cisco IOS XE Software, used in network switches and routers, contains multiple vulnerabilities related to improper input validation and other security weaknesses discovered during an internal security review. An attacker with network access could exploit these flaws to gain unauthorized access, execute commands, or disrupt network device operations without authentication.

Technologies: Cisco IOS XE. Vendors: Cisco.

Quick answers

Is CVE-2026-20273 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-20273 being exploited in the wild.
How severe is CVE-2026-20273?: High severity, with a CVSS score of 8.6, published 5 August 2026.
Which products and versions are affected?: Cisco IOS XE 17.9, 17.12, 17.15, 17.18, 26.1.
Is there a fix for CVE-2026-20273?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-20273 attacked?: It is attacked over the network, in an operating system.
Am I affected by CVE-2026-20273?: Check whether you run Cisco IOS XE 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-2026-20273 is part of a grouped disclosure addressing multiple internally discovered vulnerabilities in Cisco IOS XE Software, categorized under CWE-20 (improper input validation) among others. The vulnerabilities affect IOS XE versions 17.9, 17.12, 17.15, 17.18, and 26.1 running in autonomous or controller mode. The attack vector is network-based with no authentication required (CVSS vector AV:N/AC:L/PR:N/UI:N). Cisco has released patched versions for each affected branch (17.9.10, 17.12.8, 17.15.6, 17.18.4/4a, 26.1.2). No workarounds are available; patching is required to remediate.

Affected products

Cisco IOS XE 17.9, 17.12, 17.15, 17.18, 26.1

Timeline

2026-08-05: disclosed

References

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