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-2026-20277 CVE-2026-20278 CVE-2026-20280 CVE-2026-20279 CVE-2026-20276 CVE-2026-20275 CVE-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-2026-20355 CVE-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
CSIRTS triage
- What
- Cisco will publish security advisories on September 2, 2026 for multiple product lines including desk phones, IOS XR, Nexus switches, Silicon One, and Secure Email.
- Who is affected
- Customers using Cisco Desk Phone 9800/7800/8800/8875 series, IOS XR Software, Nexus 9000 switches, Silicon One, and Secure Email.
- Urgency
- Severity and urgency unknown; this is advance notification only with no vulnerability details yet disclosed.
- Action
- Monitor for official Cisco PSIRT advisories on September 2, 2026 and apply indicated fixed software releases.
AI-assisted analysis generated from the source advisory — verify against the original.
Details
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-20277 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20278 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20280 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20279 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20276 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20275 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20274 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20212 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20281 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20355 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-20354 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- high[NEW] [high] Cisco Nexus: Vulnerability enables execution of arbitrary code with administrator privilegescert-bund
- high[NEW] [high] Cisco IOS XR: Multiple vulnerabilities enable unspecified attackcert-bund
- medium[NEW] [medium] Cisco IP Phone: Vulnerability enables Denial of Servicecert-bund
- medium[NEW] [medium] Cisco Secure Email Gateway: Multiple vulnerabilities enable bypass of security measurescert-bund
- unknownCisco Products Multiple Vulnerabilitieshkcert
- criticalCisco IOS XR Software Security Hardening Release: September 2026cisco-psirt
- mediumCVE-2026-20355: Multiple vulnerabilities in the Secure/Multipurpose Internet Mail Extensions (S/MIME) decrypti…nvd
- mediumCVE-2026-20354: Multiple vulnerabilities in the Secure/Multipurpose Internet Mail Extensions (S/MIME) decrypti…nvd
- highCVE-2026-20281: A vulnerability in Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisc…nvd
- highCVE-2026-20280: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS…nvd
- criticalCVE-2026-20279: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS…nvd
- highCVE-2026-20278: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS…nvd
Recent advisories for Cisco Advance Notification
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- criticalCisco Advance Notification for Publication of August 19, 2026, Security Advisoriescisco-psirt · 2026-08-19
- criticalCisco Advance Notification for Publication of August 5, 2026, Security Advisoriescisco-psirt · 2026-08-05
- highCisco Advance Notification for Publication of July 15, 2026, Security Advisoriescisco-psirt · 2026-07-15
- highCisco Advance Notification for Publication of July 1, 2026, Security Advisoriescisco-psirt · 2026-07-01
More from Cisco Security Advisories
- criticalCisco IOS XR Software Security Hardening Release: September 20262026-09-02
- highCisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of …2026-09-02
- criticalCisco Nexus 9000 Series Switches Silicon One Remote Code Execution Vulnerability2026-09-02
- mediumCisco Secure Email Secure/Multipurpose Internet Mail Extensions Ciphertext Decryption Vulnerabilities2026-09-02
- criticalCisco Crosswork Security Hardening Release: August 20262026-08-21