Cisco bundles fixes for multiple vulnerabilities, some critical, into one patch
Cisco patched seven IOS XR vulnerabilities, two rated CVSS 9.8, allowing unauthenticated remote code execution and root access on carrier routers; no exploitation observed.
Cisco released fixes for seven internally discovered vulnerabilities in IOS XR, its Linux-based network operating system for carrier-grade routers. Two flaws, CVE-2026-20274 and CVE-2026-20279, are rated CVSS 9.8 (critical) and involve lifetime resource control issues that can enable unauthenticated remote code execution with root access; the other five are rated 8.2-8.8 and cover buffer overflows, access control failures, and out-of-bounds access. All IOS XR releases including IOS XR7 are affected regardless of configuration, no workarounds exist, and remediation requires software maintenance upgrades (SMUs) or fixed releases 26.2.2/26.3.1. Cisco says the flaws are not known to be actively exploited, but experts urge immediate patching of internet-facing and core routing systems, citing parallels with Salt Typhoon tradecraft.
- Two CVSS 9.8 flaws (CVE-2026-20274, CVE-2026-20279) permit unauthenticated RCE and root access on routers
- All IOS XR releases, including IOS XR7, are affected regardless of device configuration
- No workarounds available; remediation requires SMUs or future fixed releases 26.2.2 and 26.3.1
- Flaws found via internal testing, not known to be actively exploited yet
- Experts recommend prioritizing internet-facing and core routers and auditing supplier exposure
- ATT&CK
- T1190 Exploit Public-Facing ApplicationT1068 Exploitation for Privilege EscalationT1557 Adversary-in-the-Middle
- Vendors
- CiscoCisco IOS XR
- Products
- Cisco IOS XR
- Threat actors
- Salt Typhoon
- Organizations
- Info-Tech Research GroupBeauceron Security
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
CVE-2026-20274+1 related CVE | Critical Improper Resource Control Flaws in Cisco IOS XR Software | 9.8 | <1% |
From the original article
4 min read at csoonline.com
Cisco is looking to get ahead of attackers with a new set of more than a half-dozen fixes, some of them critical, for its IOS XR Linux-based network operating system (OS). As part of its regular testing, Cisco’s software engineering team flagged “multiple internally-discovered vulnerabilities,” the company said.
csoonline.com
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