EPG contract bypass in Cisco NX-OS System Software in ACI Mode
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-284.
Summary
Cisco NX-OS System Software in ACI Mode on Cisco Nexus 9000 Series Fabric Switches is affected, with many listed releases starting at 15.2(1g). The endpoint group (EPG) contract functionality has improper access control (CWE-284). An unauthenticated remote attacker can send IPv4 or IPv6 UDP packets using DHCP ports through an affected device to bypass configured EPG contracts.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
A vulnerability in the endpoint group (EPG) contract functionality of Cisco Nexus 9000 Series Fabric Switches in ACI Mode could allow an unauthenticated, remote attacker to bypass configured EPG contracts. This vulnerability is due to an improper control with EPG contracts. An attacker could exploit this vulnerability by sending IPv4 or IPv6 packets using UDP source and destination ports that are assigned to DHCP traffic through an affected device. A successful exploit could allow the attacker to bypass EPG contracts on the affected device.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Cisco | Cisco NX-OS System Software in ACI Mode | 15.2(1g); 15.2(2e); 15.2(2f); 15.2(2g); 15.2(2h); 15.2(3f); 15.2(3e); 15.2(3g); 15.2(4d); 15.2(4e); 15.2(5c); 15.2(5d); 16.0(1g); 15.2(5e); 15.2(4f); 15.2(6e); 15.2(6h); 16.0(1j); 15.2(6g); 15.2(7f); 15.2(7g); 16.0(2h); 15.2(8d); 16.0(2j); 15.2(8e); 16.0(3d); 16.0(3e); 15.2(8f); 15.2(8g); 15.3(1d); 15.2(8h); 16.0(4c); 15.3(2a); 15.2(8i); 16.0(5h); 15.3(2b); 16.0(3g); 16.0(5j); 15.3(2c); 16.0(6c); 15.3(2d); 16.1(1f); 16.0(7e); 16.0(8e); 15.3(2e); 16.0(8f); 16.1(2f); 16.1(2g); 15.3(2f); 16.0(9c); 16.1(3f); 16.0(9d); 16.0(6h); 16.0(8h); 16.1(3g); 16.0(9e); 16.1(4h); 16.1(5e); 16.2(1g); 16.0(9f); 16.2(2e) | — | No fix listed | CNA |
- Cisco NX-OS System Software in ACI Mode VendorCisco Affected 15.2(1g); 15.2(2e); 15.2(2f); 15.2(2g); 15.2(2h); 15.2(3f); 15.2(3e); 15.2(3g); 15.2(4d); 15.2(4e); 15.2(5c); 15.2(5d); 16.0(1g); 15.2(5e); 15.2(4f); 15.2(6e); 15.2(6h); 16.0(1j); 15.2(6g); 15.2(7f); 15.2(7g); 16.0(2h); 15.2(8d); 16.0(2j); 15.2(8e); 16.0(3d); 16.0(3e); 15.2(8f); 15.2(8g); 15.3(1d); 15.2(8h); 16.0(4c); 15.3(2a); 15.2(8i); 16.0(5h); 15.3(2b); 16.0(3g); 16.0(5j); 15.3(2c); 16.0(6c); 15.3(2d); 16.1(1f); 16.0(7e); 16.0(8e); 15.3(2e); 16.0(8f); 16.1(2f); 16.1(2g); 15.3(2f); 16.0(9c); 16.1(3f); 16.0(9d); 16.0(6h); 16.0(8h); 16.1(3g); 16.0(9e); 16.1(4h); 16.1(5e); 16.2(1g); 16.0(9f); 16.2(2e) Fixed in — No fix listed CNA
Remediation
The sources list no fixed version for Cisco NX-OS System Software in ACI Mode.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Timeline
- 2026-10-07 Threatist record created from CVE-2026-20038
- 2026-10-07 CISA SSVC decision points changed
- 2026-10-07 Priority changed: MEDIUM → LOW
- 2026-10-07 Alias added: GHSA-8r87-mj76-xw8h
References
Other 1
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Sources
- CVE-2026-20038 · CVE Program
- CVE-2026-20038 · NVD
- FIRST EPSS
- GHSA-8r87-mj76-xw8h · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences