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Not in CISA KEV
HIGH severity

CVE-2026-20263 — Cisco IOS XE

HIGH

CVE-2026-20263 is a high-severity (CVSS 8.6) CWE-388 vulnerability in cisco ios xe. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

A vulnerability in the Blocks Extensible Exchange Protocol (BEEP) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS)…

Published
Updated
Affected
1 product
Patched
See advisory
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-20263.

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs48th percentile — riskier than 48% of all scored CVEsHighest risk
0.00%0.36%0.72%1.07%0.3%0.6%0.6%0.6%Sep 26Nov 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Description

A vulnerability in the Blocks Extensible Exchange Protocol (BEEP) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to improper handling when parsing a specific BEEP SOAP request. An attacker could exploit this vulnerability by sending a specific BEEP SOAP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.

Affected Products

1 product · 267 configurations
OS
ios xecisco
267 versions
16.6.216.6.316.6.416.6.4a16.6.4s16.6.516.6.5a16.6.5b16.6.616.6.716.6.7a16.6.8

Detection & mitigation playbook

Vendor / appliance

  1. Detect

    Inventory every cisco ios xe deployment and check each version against the affected-products list above.

  2. Remediation status

    The records we use list no fixed version for CVE-2026-20263. Check the cisco ios xe advisory for a patched release, and apply the workarounds below until you can upgrade.

  3. Mitigate without a patch

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

A vulnerability in the Blocks Extensible Exchange Protocol (BEEP) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling when parsing a specific BEEP SOAP request. An attacker could exploit this vulnerability by sending a specific BEEP SOAP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.
O3 Security · Runtime Protection

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CVE-2026-20263: Cisco IOS XE (High 8.6)