GoKawiilLinux kernel TCP use-after-free flaw CVE-2026-98432 draws divergent severity scores
A use-after-free bug has been identified in the Linux kernel's IPv4 TCP handshake code, where a race condition between processors can leave a stale pointer to a freed IP options object. The CVE record rates it 9.8 on CVSS 3.1 as a worst-case network-reachable flaw, while Red Hat scores it 5.9 for its supported products, and Anthropic's Frontier Red Team separately demonstrated a working remote root exploit in a lab setup using a Multipath TCP listener.
GoKawiil's interpretation of the reporting above, not reported fact.
The gap between the 9.8 theoretical score, Red Hat's more conservative 5.9 assessment, and a single successful lab exploit illustrates how vulnerability scoring and real-world exploitability can diverge depending on configuration and vendor build. Anthropic's demonstrated exploit chain shows the flaw is exploitable under specific conditions, but it does not establish that all unpatched Linux systems or standard TCP listeners face the same risk. Administrators are advised to verify their specific kernel version and apply vendor patches rather than relying on any single severity figure.
- CVE-2026-98432 is a use-after-free race in the Linux kernel's TCP handshake path affecting IP options handling.
- Severity assessments differ sharply: CVSS lists 9.8 while Red Hat's product-specific score is 5.9.
- Anthropic's Frontier Red Team achieved remote root code execution in a controlled lab using a Multipath TCP listener, but this does not generalize to all configurations.
Source: penligent.ai, 2026-10-30
Published there as: “CVE-2026-98432: Linux TCP Use-After-Free Risk and Patch Validation”
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