Cisco Unified Communications Products Security Hardening Release: October 2026
cisco-sa-voice-hardening-twgbH9e3
Summary
On September 2, 2026, the Cisco Product Security Incident Response Team (PSIRT) published the following advisories:
Products covered
A separate affected-products list was not included in the collected bulletin.
4 advisories
Published advisories
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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Cisco IOS XR Software Security Hardening Release: September 2026
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Cisco Nexus 9000 Series Switches Silicon One Remote Code Execution Vulnerability
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Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of Service Vulnerability
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Cisco Secure Email Secure/Multipurpose Internet Mail Extensions Ciphertext Decryption Vulnerabilities
Remediation
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.
CVEs in this advisory 11
Update history
What changed in later vendor updates
SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.
- The vendor changed the advisory summary.
- Added CVEs: CVE-2026-20274, CVE-2026-20275, CVE-2026-20276, CVE-2026-20277, CVE-2026-20278.
- Added affected products: Published advisories.
- Removed affected products: Cisco Advance Notification for Publication of September 2, 2026, Security Advisories.
- The vendor changed the advisory summary.
- Added CVEs: CVE-2026-20212, CVE-2026-20281.
- The vendor changed its remediation guidance.
Updates
- Added to SecurityAlert
We collected the advisory from the official source.
- Published by Cisco
The publication date reported by the vendor.
- Confirmed at the source
Our collector saw this advisory during a later source check.