AI analysis
CVE-2026-76459 covers out-of-bounds write flaws (CWE-787) in Cisco NX-OS that Cisco found during an internal security review and fixed in a software hardening release. The CVSS 3.1 vector is AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score 8.8), so a remote attacker who already has low privileges can trigger the issue over the network without user interaction. Successful exploitation can lead to high impact on confidentiality, integrity, and availability of the affected device. The advisory data does not name exact NX-OS version ranges or the component that performs the write. It is not listed in CISA KEV, and no public proof-of-concept is known.
What to do: Apply the Cisco NX-OS software hardening release that addresses CVE-2026-76459 as soon as Cisco publishes fixed images for your platform, and confirm the running image against the official PSIRT advisory. Until then, restrict NX-OS management access to trusted networks, require authenticated admin access only, and watch for unexpected process crashes or memory-corruption symptoms. No public workaround details beyond that hardening release are in the available data.
Estimated exposure
largeon the order of 10,000–100,000 deployed NX-OS systems (estimate; exact count unknown) — Estimate only: NX-OS ships on widely deployed Cisco Nexus data-center and campus switches, so the installed base is plausibly in the tens of thousands of systems, but this advisory gives no install counts, version ranges, or internet-scan…
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco NX-OS engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-76459 are related to out-of-bounds write issues that are grouped under the Common Weakness Enumeration (CWE) CWE-787.