CVE-2026-73469: CWE-863 Incorrect Authorization in Arista Networks EOS
When specific platforms are using Arista EOS with a loose Unicast Reverse Path Forwarding (uRPF) configuration, certain traffic may not be subjected to the intended verification drop. Consequently, traffic that should be dropped based on these routes could still be processed and forwarded by the device. This issue was discovered internally by Arista and the company is not aware of any malicious uses of this issue in customer networks.
AI Analysis
Technical Summary
This vulnerability in Arista EOS arises when specific platforms use a loose uRPF configuration, causing the device to fail to drop certain traffic that should be blocked by route verification. This incorrect authorization (CWE-863) could lead to unauthorized traffic forwarding. The issue affects EOS versions from 4.35.0F through 4.35.4M. Arista discovered this internally and is not aware of any active exploitation in the wild.
Potential Impact
The vulnerability allows some traffic that should be dropped by uRPF verification to be forwarded by the device, potentially enabling unauthorized traffic flow. There is no reported impact on confidentiality or availability, but integrity could be impacted due to unauthorized traffic forwarding. No known exploits have been observed in customer environments.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch links or official fixes are provided, users should monitor Arista's advisories for updates. Until a fix is available, review and tighten uRPF configurations where possible to reduce exposure.
CVE-2026-73469: CWE-863 Incorrect Authorization in Arista Networks EOS
Description
When specific platforms are using Arista EOS with a loose Unicast Reverse Path Forwarding (uRPF) configuration, certain traffic may not be subjected to the intended verification drop. Consequently, traffic that should be dropped based on these routes could still be processed and forwarded by the device. This issue was discovered internally by Arista and the company is not aware of any malicious uses of this issue in customer networks.
CVSS v3.1
Score 5.8medium
Affected software
Arista Networks
EOS
pkg:github/aristanetworks/eosRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in Arista EOS arises when specific platforms use a loose uRPF configuration, causing the device to fail to drop certain traffic that should be blocked by route verification. This incorrect authorization (CWE-863) could lead to unauthorized traffic forwarding. The issue affects EOS versions from 4.35.0F through 4.35.4M. Arista discovered this internally and is not aware of any active exploitation in the wild.
Potential Impact
The vulnerability allows some traffic that should be dropped by uRPF verification to be forwarded by the device, potentially enabling unauthorized traffic flow. There is no reported impact on confidentiality or availability, but integrity could be impacted due to unauthorized traffic forwarding. No known exploits have been observed in customer environments.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no patch links or official fixes are provided, users should monitor Arista's advisories for updates. Until a fix is available, review and tighten uRPF configurations where possible to reduce exposure.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Arista
- Date Reserved
- 2026-08-12T16:47:18.121Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aaa692755bf5e2cf553d91b
Added to database: 09/16/2026, 10:02:15 UTC
Last enriched: 09/16/2026, 10:16:36 UTC
Last updated: 09/16/2026, 10:32:25 UTC
Views: 5
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