CVE-2026-121290
Security Advisory 0209
On affected platforms running Arista EOS with Border Gateway Protocol (BGP) changing the BGP listen port from its default value disables default protective Access Control List (ACL) rules against unexpected BGP peering attempts.
Fixes and workarounds
Workaround
router bgp <asn> no bgp transport listen-port If the non-default listen port must be retained, the required modifications to the control plane ACL (to allow the non-default listen port to be reached) should be made in such a manner to provide the desired protection — only allowing TCP connections using the non-default listen port when the remote IP address is an expected one, and if applicable, when the TTL value is within the expected range.
Source: CNA: AristaAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| EOS Arista Networks 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 |
≥ 4.36.0F; ≤ 4.36.2F (affected, custom) ≥ 4.35.0F; ≤ 4.35.6M (affected, custom) ≥ 4.34.0F; ≤ 4.34.8M (affected, custom) ≥ 4.33.0F; ≤ 4.33.10M (affected, custom) ≥ 4.32.0F; < 4.33.0F (affected, custom) ≥ 1.0.0; < 4.32.0F (affected, custom) Other versions: unaffected |
CNA: Arista |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 8.2 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H | CNA: Arista |
| 4.0 / 8.3 high |
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N | CNA: Arista |
| 4.0 / 8.3 high |
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/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 | NVD: [email protected] |
| 3.1 / 8.2 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
For agents and automation
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