Cisco Security Advisoriescisco-sa-notice-f2SiMFxl

Cisco Advance Notification for Publication of September 2, 2026, Security Advisories

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-2026-20277CVE-2026-20278CVE-2026-20280CVE-2026-20279CVE-2026-20276CVE-2026-20275CVE-2026-20274 Critical 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-2026-20355CVE-2026-20354 Medium 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. Security Impact Rating: Informational

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InformationalCVSS not listedInformational severity

Scope

What the vendor says is affected

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Update history

What changed in later vendor updates

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Sep 2, 2026 at 4:10 PM UTC
- The vendor changed the advisory summary.
- Added CVEs: CVE-2026-20212, CVE-2026-20281.
- The vendor changed its remediation guidance.

Timeline

When this advisory changed

Aug 26, 2026 at 4:10 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.
Sep 2, 2026 at 4:02 PM UTC
Published by Cisco
The publication date reported by the vendor.
Sep 13, 2026 at 4:50 AM UTC
Confirmed at the source
Our collector saw this advisory during a later source check.

Vulnerabilities

CVEs named in this advisory

CVE-2026-20212View CVSS, KEV, EPSS, and threat context CVE-2026-20281View CVSS, KEV, EPSS, and threat context

Source

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Vendor: Cisco
Advisory ID: cisco-sa-notice-f2SiMFxl
Last source check: Sep 13, 2026 at 4:50 AM UTC

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What the vendor says is affected

What changed in later vendor updates

When this advisory changed

CVEs named in this advisory

Related advisories from Cisco

Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of Service Vulnerability

Cisco Nexus 9000 Series Switches Silicon One Remote Code Execution Vulnerability

Cisco IOS XR Software Security Hardening Release: September 2026

Cisco Secure Firewall Management Center Software Authentication Bypass Vulnerability

Cisco Advance Notification for Publication of September 16, 2026, Security Advisories

Cisco UCS and UCS-Based Appliances UEFI Shell Secure Boot Bypass Vulnerability