Cisco Nx Os System Software In Aci Mode
Monthly
Remotely triggerable denial-of-service conditions in Cisco NX-OS Software - including NX-OS System Software running in ACI mode and managed Cisco Unified Computing System deployments - can cause an affected device to reload or otherwise become unavailable. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H, base 8.6) describes an unauthenticated, low-complexity, network-reachable flaw with availability-only impact and scope change, meaning the affected process can degrade resources beyond its own security boundary, but there is no confidentiality or integrity impact and no public exploit code identified at time of analysis. The issue was found during Cisco's own internal security review and is delivered as a grouped software hardening release rather than a single named feature fix, so the precise triggering traffic or configuration is not disclosed; the practical risk is loss of availability of data-center switching and fabric devices that are reachable from an untrusted network segment.
Out-of-bounds write defects in Cisco NX-OS Software - spanning standalone NX-OS switches, NX-OS System Software running in ACI mode, and NX-OS-based software managed through Cisco UCS - carry a vendor CVSS of 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), meaning a remote, unauthenticated attacker with network reachability could potentially cause high confidentiality, integrity, and availability impact. The issues were discovered during a Cisco internal security review and are delivered as part of a bundled software hardening release rather than a single pinpointed defect, so the affected subsystem, protocol, or port is not enumerated in the available data. At time of analysis there is no public exploit identified, CISA SSVC records exploitation as 'none' with automatable 'no', and EPSS is low at 0.28% (19th percentile), indicating manual, targeted rather than scalable risk.
Improper access control in Cisco NX-OS - including NX-OS running in ACI mode and the NX-OS component of managed Cisco Unified Computing System deployments - could allow a remote, unauthenticated attacker to bypass access restrictions and achieve full compromise of confidentiality, integrity, and availability (CVSS 3.1 9.8, AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). The issue was identified during a Cisco internal security review and is addressed in a NX-OS software hardening release rather than a single-point bug fix, with the advisory grouping multiple internally discovered access-control weaknesses under CVE-2026-76455. At time of analysis no public exploit code or confirmed active exploitation has been identified, and the specific vulnerable feature, protocol, or configuration mode is not disclosed in the available data, so exposure must be validated against the Cisco advisory before triage.
Out-of-bounds read issues in Cisco NX-OS, NX-OS in ACI mode, and managed Cisco UCS software can be triggered by remote, unauthenticated attackers to cause a denial-of-service condition (process crash/restart) on affected devices. The CVSS 3.1 score is 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H), and exploitation is limited by reachability to the vulnerable management/control-plane service, which is often segmented on management VLANs or trusted networks. No public exploit code or confirmed active exploitation was identified in the provided data, and Cisco's advisory does not name a specific protocol, port, or feature beyond the hardening release.
Unauthenticated, network-reachable input-validation flaws in Cisco NX-OS Software command processing can disrupt affected devices, and the same hardening advisory covers Cisco NX-OS System Software running in ACI mode as well as the NX-OS component of Cisco Unified Computing System (managed). Cisco scores it 8.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H), so the assessed impact is availability-only with a scope change and no confidentiality or integrity effect. The issue was discovered during Cisco's internal security review and is addressed by a hardening release rather than by any observed attack activity, and no public exploit code or CISA KEV entry is associated with it at time of analysis.
Improper neutralization of input in Cisco NX-OS software, NX-OS System Software running in ACI mode, and Cisco Unified Computing System (Managed) allows an authenticated attacker holding low-privilege credentials to reach high confidentiality, integrity, and availability impact against the affected device (CVSS 3.1: 8.8, AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). The flaw surfaced during Cisco's internal security review and is remediated through a software hardening release rather than through an out-of-band emergency fix, which indicates internally discovered rather than customer-reported or externally exploited issues. There is no public exploit code and no confirmed active exploitation at time of analysis, though the network-reachable attack path and the breadth of affected platforms (standalone Nexus switches, ACI-mode fabrics, and UCS Managed systems) make it a credible operational priority despite the absence of exploitation signals.
EPG contract bypass in Cisco Nexus 9000 Series Fabric Switches running ACI Mode allows an unauthenticated, remote attacker to evade configured endpoint-group segmentation by sending IPv4 or IPv6 UDP packets with DHCP source and destination ports (67/68) through the device. The flaw is an improper access-control implementation (CWE-284) rated CVSS 5.8 with scope change and low integrity impact; no public exploit identified at time of analysis. Exploitation requires ACI mode and EPG contracts in use, and the attacker must have a network path through the switch; it does not directly disclose data or cause denial of service.
Remotely triggerable denial-of-service conditions in Cisco NX-OS Software - including NX-OS System Software running in ACI mode and managed Cisco Unified Computing System deployments - can cause an affected device to reload or otherwise become unavailable. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H, base 8.6) describes an unauthenticated, low-complexity, network-reachable flaw with availability-only impact and scope change, meaning the affected process can degrade resources beyond its own security boundary, but there is no confidentiality or integrity impact and no public exploit code identified at time of analysis. The issue was found during Cisco's own internal security review and is delivered as a grouped software hardening release rather than a single named feature fix, so the precise triggering traffic or configuration is not disclosed; the practical risk is loss of availability of data-center switching and fabric devices that are reachable from an untrusted network segment.
Out-of-bounds write defects in Cisco NX-OS Software - spanning standalone NX-OS switches, NX-OS System Software running in ACI mode, and NX-OS-based software managed through Cisco UCS - carry a vendor CVSS of 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), meaning a remote, unauthenticated attacker with network reachability could potentially cause high confidentiality, integrity, and availability impact. The issues were discovered during a Cisco internal security review and are delivered as part of a bundled software hardening release rather than a single pinpointed defect, so the affected subsystem, protocol, or port is not enumerated in the available data. At time of analysis there is no public exploit identified, CISA SSVC records exploitation as 'none' with automatable 'no', and EPSS is low at 0.28% (19th percentile), indicating manual, targeted rather than scalable risk.
Improper access control in Cisco NX-OS - including NX-OS running in ACI mode and the NX-OS component of managed Cisco Unified Computing System deployments - could allow a remote, unauthenticated attacker to bypass access restrictions and achieve full compromise of confidentiality, integrity, and availability (CVSS 3.1 9.8, AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). The issue was identified during a Cisco internal security review and is addressed in a NX-OS software hardening release rather than a single-point bug fix, with the advisory grouping multiple internally discovered access-control weaknesses under CVE-2026-76455. At time of analysis no public exploit code or confirmed active exploitation has been identified, and the specific vulnerable feature, protocol, or configuration mode is not disclosed in the available data, so exposure must be validated against the Cisco advisory before triage.
Out-of-bounds read issues in Cisco NX-OS, NX-OS in ACI mode, and managed Cisco UCS software can be triggered by remote, unauthenticated attackers to cause a denial-of-service condition (process crash/restart) on affected devices. The CVSS 3.1 score is 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H), and exploitation is limited by reachability to the vulnerable management/control-plane service, which is often segmented on management VLANs or trusted networks. No public exploit code or confirmed active exploitation was identified in the provided data, and Cisco's advisory does not name a specific protocol, port, or feature beyond the hardening release.
Unauthenticated, network-reachable input-validation flaws in Cisco NX-OS Software command processing can disrupt affected devices, and the same hardening advisory covers Cisco NX-OS System Software running in ACI mode as well as the NX-OS component of Cisco Unified Computing System (managed). Cisco scores it 8.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H), so the assessed impact is availability-only with a scope change and no confidentiality or integrity effect. The issue was discovered during Cisco's internal security review and is addressed by a hardening release rather than by any observed attack activity, and no public exploit code or CISA KEV entry is associated with it at time of analysis.
Improper neutralization of input in Cisco NX-OS software, NX-OS System Software running in ACI mode, and Cisco Unified Computing System (Managed) allows an authenticated attacker holding low-privilege credentials to reach high confidentiality, integrity, and availability impact against the affected device (CVSS 3.1: 8.8, AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). The flaw surfaced during Cisco's internal security review and is remediated through a software hardening release rather than through an out-of-band emergency fix, which indicates internally discovered rather than customer-reported or externally exploited issues. There is no public exploit code and no confirmed active exploitation at time of analysis, though the network-reachable attack path and the breadth of affected platforms (standalone Nexus switches, ACI-mode fabrics, and UCS Managed systems) make it a credible operational priority despite the absence of exploitation signals.
EPG contract bypass in Cisco Nexus 9000 Series Fabric Switches running ACI Mode allows an unauthenticated, remote attacker to evade configured endpoint-group segmentation by sending IPv4 or IPv6 UDP packets with DHCP source and destination ports (67/68) through the device. The flaw is an improper access-control implementation (CWE-284) rated CVSS 5.8 with scope change and low integrity impact; no public exploit identified at time of analysis. Exploitation requires ACI mode and EPG contracts in use, and the attacker must have a network path through the switch; it does not directly disclose data or cause denial of service.