Cisco Security Advisory
Cisco Advance Notification for Publication of September 2, 2026, Security Advisories
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On September 2, 2026, the Cisco Product Security Incident Response Team (PSIRT) published the following advisories:
Cisco Security Advisory CVE ID Security Impact Rating CVSS Base Score Cisco IOS XR Software Security Hardening Release: September 2026 CVE-2026-20277
CVE-2026-20278
CVE-2026-20280
CVE-2026-20279
CVE-2026-20276
CVE-2026-20275
CVE-2026-20274Critical 9.8 Cisco Nexus 9000 Series Switches Silicon One Remote Code Execution Vulnerability CVE-2026-20212 Critical 9.8 Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of Service Vulnerability CVE-2026-20281 High 7.5 Cisco Secure Email Secure/Multipurpose Internet Mail Extensions Ciphertext Decryption Vulnerabilities CVE-2026-20355
CVE-2026-20354Medium 5.9 To remediate the vulnerabilities that were disclosed on September 2, 2026, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories.
For more information about changes in Cisco PSIRT vulnerability disclosure, see Strengthening the Foundation: A Predictable, Customer-Focused Response to AI-Accelerated Vulnerability Discovery.
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Under the Cisco risk-based disclosure process, hardening releases and other security advisories are scheduled to publish on the first and third Wednesday of each month. To help customers prepare, we provide this seven-day advance notice of upcoming security vulnerability disclosures. However, this schedule is not a final commitment of releases. If updates are delayed or unforeseen changes arise, specific products may be removed and rescheduled. Products may also be added when releases are ready ahead of schedule. The latest status is available in the Revision History section of this advance notice.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
For additional information on Cisco's vulnerability management, disclosure cadence, and software patching strategy, see Cisco's Transition to a Risk-Based Vulnerability Disclosure Model.
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Show LessVersion Description Section Status Date 1.1 Added links to security advisories. Summary Final 2026-SEP-02 1.0 Initial public release. - Interim 2026-AUG-26
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SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT
The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool. Please note that customers may download only software that was procured from Cisco directly or through a Cisco authorized reseller or partner and for which the license is still valid.
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC). Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
When considering software upgrades, customers are advised to regularly consult the advisories for the relevant Cisco products to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
LEGAL DISCLAIMER DETAILS
CISCO DOES NOT MAKE ANY EXPRESS OR IMPLIED GUARANTEES OR WARRANTIES OF ANY KIND, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, CISCO DOES NOT GUARANTEE THE ACCURACY OR COMPLETENESS OF THIS INFORMATION. THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
Copies or summaries of the information contained in this Security Advisory may lack important information or contain factual errors. Customers are advised to visit the Cisco Security Advisories page for the most recent version of this Security Advisory. The Cisco Product Security Incident Response Team (PSIRT) assesses only the affected and fixed release information that is documented in this advisory. See the Cisco Security Vulnerability Policy for more information.