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CVE-2026-20276— Cisco IOS XR Software Security Hardening Release: September 2026

Quick assessment

Affected
Cisco Cisco IOS XR Software
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

作为思科（Cisco）持续推进主动安全与产品质量承诺的一部分，思科 IOS XR 软件工程团队进行了一次全面的内部安全审查。该审查得出了若干经过强化的软件版本，用于修复多个在内部发现的安全漏洞。 由 CVE-2026-20276 追踪的漏洞与控制流管理不足的问题相关，这些问题归属于通用弱点枚举（CWE）中的 CWE-691。

CVSS 8.6 · High

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 111

VendorProduct Version RangeStatus
Cisco Cisco IOS XR Software 6.5.29 affected
7.0.1 affected
6.5.26 affected
6.5.25 affected
6.5.28 affected
6.5.90 affected
7.1.1 affected
7.0.90 affected
… +103 more rows
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I. Basic Information for CVE-2026-20276

Vulnerability Information
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Vulnerability Title
Cisco IOS XR Software Security Hardening Release: September 2026
Source: CVE Program / CVE List V5
Vulnerability Description
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20276 are related to insufficient control flow management issues that are grouped under the Common Weakness Enumeration (CWE) CWE-691.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不充分的控制流管理
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Cisco Cisco IOS XR Software 6.5.29 -

II. Public POCs for CVE-2026-20276

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III. Intelligence Information for CVE-2026-20276

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Vendor Advisories for CVE-2026-20276 (1)

Same Patch Batch · Cisco · 2026-09-02 · 11 CVEs total

CVE-2026-20279 9.8 CRITICAL Cisco IOS XR Software Security Hardening Release: September 2026
CVE-2026-20274 9.8 CRITICAL Cisco IOS XR Software Security Hardening Release: September 2026
CVE-2026-20212 9.8 CRITICAL Cisco Nexus 3000 and 9000 Series Switches Silicon One Hardware Abstraction Layer Remote Co
CVE-2026-20280 8.8 HIGH Cisco IOS XR Software Security Hardening Release: September 2026
CVE-2026-20278 8.8 HIGH Cisco IOS XR Software Security Hardening Release: September 2026
CVE-2026-20275 8.8 HIGH Cisco IOS XR Software Security Hardening Release: September 2026
CVE-2026-20277 8.2 HIGH Cisco IOS XR Software Security Hardening Release: September 2026
CVE-2026-20281 7.5 HIGH Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP
CVE-2026-20355 5.9 MEDIUM Cisco Secure Email S/MIME Ciphertext Decryption Vulnerabilty
CVE-2026-20354 5.9 MEDIUM Cisco Secure Email S/MIME Ciphertext Decryption Vulnerabilty

IV. Related Vulnerabilities

Same product: Cisco IOS XR Software
Same vendor: Cisco
Same weakness: CWE-691

V. Comments for CVE-2026-20276

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