This report was translated by AI; nobody has reviewed the translation yet. Original language: Czech.

[TLP:CLEAR] Cisco fixes 9 vulnerabilities

Cisco fixes 9 vulnerabilities in its products, 3 of them critical in Cisco IOS XR and Cisco Nexus 9000 Series [1][2]. The vulnerability in Cisco Nexus 9000 is described below; the remaining vulnerabilities can be found at [1][3]. Products and their fixes: Cisco IOS XR - SMUs available: 7.3.2, 7.9.2, 7.9.21, 7.10.2, 7.11.2, 7.11.21, 24.2.2, 24.2.21, 24.4.2, 25.2.21, 25.4.1, 25.4.2, 26.1.2, 26.2.1 [1] - SMUs in preparation: 24.1.2, 24.3.2, 25.1.2, 25.2.2 [1] - first fixed releases without the need for an SMU: 26.2.2, 26.3.1 (future release) [1] Cisco SIP Software - 5.0(1), 14.4(1)SR3, 14.4(1)SR4, 11.0(6)SR8 [3] Cisco Nexus 9000 Series Switches - fix availability can be verified using the Cisco Software Checker tool [4]

Cisco Nexus 9000 - RCE (CVE-2026-20212)
CVSS 9.8 (Critical)

An unauthenticated remote attacker can execute arbitrary code with root privileges using specially crafted input due to TCP ports 43210 and 43211 being reachable in the default L3 VRF on Cisco Nexus 9000 switches. Only the models with Silicon One ASIC listed in the advisory are affected [2]. To limit remote exploitation, it is recommended to use iACL rules that permit only necessary traffic and block TCP communication to ports 43210 and 43211; alternatively, Cisco offers a temporary Live Protect shield lp00031 [2][5].

The vulnerability is present in product:

  • Cisco NX-OS Software;

CVSS: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X

More information:

The vulnerability was publicly disclosed 2. 9. 2026.

By CESNET, z.s.p.o. Michaela Jarošová on 4. 9. 2026.

CESNET, z.s.p.o. Logo