CVE-2025-6188

Summary

On affected platforms running Arista EOS, maliciously formed UDP packets with source port 3503 may be accepted by EOS. UDP Port 3503 is associated with LspPing Echo Reply. This can result in unexpected behaviors, especially for UDP based services that do not perform some form of authentication.

Affected Software

Weaknesses

• 288

Workarounds

For EOS versions more recent than 4.28.1, if MPLS is not being used on the EOS device, a custom control plane ACL can be applied to remove the rules that allow traffic with source port 3503.

Switch(config)#system control-plane Switch(config-cp)#ip access-group my-custom-acl

For EOS versions more recent than 4.22.0, an ‘mpls ping’ service ACL can be applied to restrict traffic coming with source/destination port 3503. This service ACL is applicable on the traffic coming in with source/destination port 3503. MPLS configuration is not required to apply the ACL.

Take the following example, where the user applies service ACL ‘Foo’ that allows traffic from 10.0.0.0/8 with source port 3503 and denies everything else.

Switch(config)#ip access-list Foo Switch(config-acl-foo)#permit udp 10.0.0.0/8 eq lsp-ping any Switch(config-acl-foo)#deny udp any eq lsp-ping any

Switch(config)#mpls ping Switch(config-mpls-ping)#ip access-group foo in

If MPLS is not being used, it is fine to only have the deny rule in the ACL. For EOS versions older than 4.22.0 no mitigation exists.

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

References

• https://www.arista.com/en/support/advisories-notices/security-advisory/22021-security-advisory-0121

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