Medium · CVSS 6.1CVE-2026-121288

Security Advisory 0221CVE-2026-121288

Answer in brief

CVE-2026-121288 records a Medium severity (CVSS 6.1) vulnerability in Security Advisory 0221. The current sources do not mark it as known exploited. The current feed maps Arista Networks/EOS (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Nov 10, 2026Updated Nov 10, 2026Source checked Nov 10, 2026First seen by HOL Nov 10, 2026Material review Nov 10, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 6.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Arista Networks/EOS (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Arista Networks/EOSgeneric	4.37.0F \|\| >=4.36.0F <=4.36.2F \|\| >=4.35.0F <=4.35.6M \|\| >=4.34.0F <=4.34.8M \|\| >=4.33.0F <=4.33.10M \|\| >=4.32.0F <4.33.0F \|\| >=1.0.0 <4.32.0F	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Arista Networks/EOS.
Review the reported fix. Source-reported 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.

Evidence timeline and material changes

Published upstream
Nov 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Nov 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Nov 10, 2026

Sources and claim methodology

Source referencearista.com

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

Affected scope and exposure questions

The current feed maps Arista Networks/EOS (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Arista Networks/EOSgeneric	4.37.0F \|\| >=4.36.0F <=4.36.2F \|\| >=4.35.0F <=4.35.6M \|\| >=4.34.0F <=4.34.8M \|\| >=4.33.0F <=4.33.10M \|\| >=4.32.0F <4.33.0F \|\| >=1.0.0 <4.32.0F	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Arista Networks/EOS.

Review the reported fix. Source-reported 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.

Sources and claim methodology

Upstream source description

Quoted source text, attributed separately from HOL analysis.