CVE-2026-20171 (GCVE-0-2026-20171)
Vulnerability from cvelistv5
Published
2026-05-20 16:06
Modified
2026-05-20 18:31
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-670 - Always-Incorrect Control Flow Implementation
Summary
A vulnerability in the Border Gateway Protocol (BGP) enforce-first-as feature of Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, remote attacker to trigger BGP peer flaps, resulting in a denial of service (DoS) condition.
This vulnerability is due to incorrect parsing of a transitive BGP attribute. An attacker could exploit this vulnerability by sending a crafted BGP update through an established BGP peer session. If the update propagates to an affected device, it could cause the device to drop the BGP session and flap with the BGP peer that is forwarding this update, resulting in a DoS condition.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Cisco | Cisco NX-OS Software |
Version: 10.2(1) Version: 10.2(1q) Version: 10.2(2) Version: 10.2(3) Version: 10.2(3t) Version: 10.2(2a) Version: 10.3(1) Version: 10.2(4) Version: 10.3(2) Version: 10.3(3) Version: 10.2(5) Version: 10.2(3v) Version: 10.4(1) Version: 10.3(99w) Version: 10.2(6) Version: 10.3(3w) Version: 10.3(99x) Version: 10.3(3o) Version: 10.3(4) Version: 10.3(3p) Version: 10.3(4a) Version: 10.4(2) Version: 10.3(3q) Version: 10.3(5) Version: 10.2(7) Version: 10.4(3) Version: 10.3(3x) Version: 10.3(4g) Version: 10.5(1) Version: 10.2(8) Version: 10.3(3r) Version: 10.3(6) Version: 10.4(4) Version: 10.3(4h) Version: 10.5(2) Version: 10.3(7) Version: 10.4(5) Version: 10.5(3) Version: 10.2(9) Version: 10.4(4g) Version: 10.6(1) Version: 10.5(3t) Version: 10.3(8) Version: 10.4(6) Version: 10.5(3s) Version: 10.5(3e) Version: 10.5(3o) Version: 10.6(1s) Version: 10.5(3p) |
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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