CVE-2026-121288

Security Advisory 0221

Published Nov 10, 2026 CVSS 4.0 · 6.1 Medium EPSS < 1% KEV · Not listed

Description

An unauthenticated attacker on an adjacent network segment can bypass MD5 authentication and have unauthorized RIP route updates accepted by the device. Successful exploitation requires that RIPv2 MD5 authentication is configured on the affected interface. An attacker who can inject crafted RIPv2 packets could cause the device to install routes that redirect network traffic through attacker-controlled paths, create routing loops, or blackhole traffic, disrupting network connectivity.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Arista Networks

EOS

unaffected

Version	Status	Constraints
`4.37.0F`	affected	—
`4.36.0F`	affected	≤ 4.36.2F
`4.35.0F`	affected	≤ 4.35.6M
`4.34.0F`	affected	≤ 4.34.8M
`4.33.0F`	affected	≤ 4.33.10M
`4.32.0F`	affected	< 4.33.0F
`1.0.0`	affected	< 4.32.0F

No data.

Vendor Product Versions

Arista

Eos

Version	Status	Scheme	Platform
`4.37.0F`	affected	generic	['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', 'cloudeos', 'ceos-lab', 'veos-lab', 'cloudvision_exchange,_virtual_or_physical_appliance']
`[4.36.0F,4.36.2F]`	affected	generic	['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', 'cloudeos', 'ceos-lab', 'veos-lab', 'cloudvision_exchange,_virtual_or_physical_appliance']
`[4.35.0F,4.35.6M]`	affected	generic	['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', 'cloudeos', 'ceos-lab', 'veos-lab', 'cloudvision_exchange,_virtual_or_physical_appliance']
`[4.34.0F,4.34.8M]`	affected	generic	['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', 'cloudeos', 'ceos-lab', 'veos-lab', 'cloudvision_exchange,_virtual_or_physical_appliance']
`[4.33.0F,4.33.10M]`	affected	generic	['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', 'cloudeos', 'ceos-lab', 'veos-lab', 'cloudvision_exchange,_virtual_or_physical_appliance']
`[4.32.0F,4.33.0F)`	affected	generic	['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', 'cloudeos', 'ceos-lab', 'veos-lab', 'cloudvision_exchange,_virtual_or_physical_appliance']
`[1.0.0,4.32.0F)`	affected	generic	['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', 'cloudeos', 'ceos-lab', 'veos-lab', 'cloudvision_exchange,_virtual_or_physical_appliance']

Remediation

Vendor Workaround

switch(config)# router rip switch(config-router-rip)# shutdown switch(config-router-rip)# end Note: disabling RIP or changing network statements may withdraw routes and interrupt connectivity. Plan a change window, confirm alternate routing, and verify the resulting configuration and route behavior.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact Low

Subsequent System Availability Impact Low

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.236% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://www.arista.com/en/support/advisories-notices/security-advisory/25043-security-advisory-0221

History

Nov 12, 2026 3:30 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Arista Arista eos
Vendors & Products		Arista Arista eos

Nov 10, 2026 8:15 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		An unauthenticated attacker on an adjacent network segment can bypass MD5 authentication and have unauthorized RIP route updates accepted by the device. Successful exploitation requires that RIPv2 MD5 authentication is configured on the affected interface. An attacker who can inject crafted RIPv2 packets could cause the device to install routes that redirect network traffic through attacker-controlled paths, create routing loops, or blackhole traffic, disrupting network connectivity.
Title		Security Advisory 0221
Weaknesses		CWE-303
References		https://www.arista.com/en/support/advisories-notices/security-advisory/25043-security-advisory-0221
Metrics		cvssV3_1 `{'score': 8.1, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H'}` cvssV4_0 `{'score': 6.1, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:L/SA:L'}`