# CVE-2026-121367: Security Advisory 0220

Status: published. Published: 2026-11-10. Updated: 2026-11-13.

On affected Arista EOS platforms with Routing Information Protocol version 2 (RIPv2) configured, under certain conditions, RIPv2 might be silently enabled on management interfaces even when the RIP agent intends to disable it. It allows an unauthenticated attacker with access to the adjacent network to send crafted RIPv2 route advertisements to the device's management IP address. The device could accept and install those routes without authentication.

Successful exploitation could allow the attacker to redirect traffic flows to an attacker-controlled destination, install more-specific routes that blackhole legitimate traffic, or otherwise disrupt network reachability for systems whose traffic passes through the affected device.

## Remediation

- workaround: switch# configure terminal
switch(config)# router rip
switch(config-router-rip)# shutdown
switch(config-router-rip)# end

(Workaround: In environments where RIP is not required, disable it within each affected VRF instance. If RIP is necessary on data interfaces but not the management subnet, verify no RIP network prefix matches the management subnet.) (source: CNA: Arista)

## Affected products and versions

- Arista Networks / EOS: ≥ 1.0.0; < 4.33.0F (affected, custom); ≥ 4.33.0F; ≤ 4.33.10M (affected, custom); ≥ 4.34.0F; ≤ 4.34.8M (affected, custom); ≥ 4.35.0F; ≤ 4.35.6M (affected, custom); ≥ 4.36.0F; ≤ 4.36.2F (affected, custom); 4.37.0F (affected, custom). Source: CNA: Arista; platforms: 710 Series, 720D Series, 720XP/722XPM Series, 750X Series, 7010TX Series, 7020R/R4 Series, 7130 Series running EOS, 7170 Series, 7050X3/X4 Series, 7060X/X2/X4/X5/X6/XE7 Series, 7260X/X3 Series, 7280R/R2/R3/R4 Series, 7300X/X3 Series, 7320X Series, 7358X4 Series, 7368X4 Series, 7388X5 Series, 7500R/R2/R3 Series, 7800R3/R4 Series, 7700R4 Series, AWE 5000 Series, AWE 7200R Series, ZTX-7200 Series, CloudEOS, cEOS-lab, vEOS-lab, CloudVision eXchange, virtual or physical appliance

## Severity and prioritization

- CVSS 3.1: 9.6 (critical); CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H; source: CNA: Arista

- CVSS 4.0: 6.1 (medium); CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:H/SC:N/SI:L/SA:L; source: CNA: Arista

- CVSS 4.0: 6.1 (medium); CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:H/SC:N/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: psirt@arista.com

- CVSS 3.1: 9.6 (critical); CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H; source: NVD: psirt@arista.com

- CISA KEV: No listing in collected sources

- EPSS: 0.29% as of 2026-11-13; percentile 22.05%

- SSVC: exploitation none; automatable yes; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-440

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://www.arista.com/en/support/advisories-notices/security-advisory/25042-security-advisory-0220 (CNA: Arista; vendor-advisory)

- https://www.arista.com/en/support/advisories-notices/security-advisory/25042-security-advisory-0220 (psirt@arista.com)

## Provenance

- CNA: Arista: https://www.cve.org/CVERecord?id=CVE-2026-121367; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-121367; retrieved 2026-11-13; source updated 2026-11-12

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-121367; retrieved 2026-11-13; source updated Not reported

Revision: 7741587c6b87a7fa90b24780e75300d13821c52782e8c8c0df8f96bbd01eb2cf

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