CVE-2026-23451: 
Linux Kernel vulnerability analysis and mitigation

CVE-2026-23451 is a Linux kernel vulnerability involving a potential infinite loop in the bond_header_parse() function within the bonding network driver. When a stack of two bonding devices is configured, skb->dev always points to the hierarchy top, causing the function to loop indefinitely. The vulnerability affects Linux kernel versions up to and including 6.18.19, 6.19.9, and 7.0-rc4, with fixes available in 6.18.20, 6.19.10, and 7.0-rc5. It was disclosed on April 3, 2026, and carries a CVSS v3.1 base score of 7.5 (High) (GitHub Advisory).

The root cause is classified as CWE-835 (Loop with Unreachable Exit Condition / Infinite Loop). In the Linux kernel's bonding subsystem, bond_header_parse() calls the (struct header_ops)->parse() method, which uses skb->dev to determine the network device. When two bonding devices are stacked, skb->dev consistently references the top of the device hierarchy rather than the leaf device, causing unbounded recursive calls. The fix introduces a new const struct net_device *dev parameter to the (struct header_ops)->parse() method, ensuring recursion is bounded and the correct leaf-level parse method is ultimately invoked (GitHub Advisory).

Successful triggering of this vulnerability results in a denial-of-service condition through resource exhaustion or system hang on affected Linux hosts. There is no confidentiality or integrity impact — only availability is affected. Systems utilizing multi-level bonded network interface configurations (e.g., bond-over-bond setups) are specifically at risk of service interruption, potentially impacting network-dependent workloads and high-availability infrastructure (GitHub Advisory).

There is no known public proof-of-concept exploit and no evidence of in-the-wild exploitation at this time. The EPSS score is approximately 0.018% (0.000180), indicating a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires the ability to trigger packet processing through a stacked bonding device configuration, which limits the practical attack surface (GitHub Advisory).

Update the Linux kernel to a patched version: 6.18.20, 6.19.10, or 7.0-rc5 and later. Patches are available via the following stable kernel commits: 946bb6cacf0ccada7bc80f1cfa07c1ed79511c1c, 4172a7901cf43fe1cc63ef7a2ef33735ff7b7d13, 9b49c854f14f5e2d493e562a1e28d2e57fe37371, and b7405dcf7385445e10821777143f18c3ce20fa04. As a configuration-level workaround, administrators should audit and avoid stacked (bond-over-bond) bonding device configurations where possible until patching is complete. Monitor system logs and interface performance for signs of infinite loops or CPU exhaustion on bonded interfaces (GitHub Advisory).