Technology
Linux kernel TCP flaw CVE-2026-98432 draws differing severity scores
Hacker News reports a Linux kernel IPv4 TCP use-after-free flaw, with severity scores varying by issuer and an upstream patch merged.
The short version
- Hacker News reports CVE-2026-98432 is a use-after-free flaw in the Linux kernel's IPv4 TCP handshake path.[Hacker News]
- Issuers differ on severity: the Linux CNA record lists CVSS 9.8, while Red Hat lists a preliminary 8.1.[Hacker News]
- Anthropic's Frontier Red Team reported remote root command execution on a Multipath TCP listener in a controlled lab, not universal compromise.[Hacker News]
- An upstream patch, commit e3f33b0a1d89, delays memory reclamation until an RCU grace period; no authoritative source establishes widespread exploitation.[Hacker News]
Key facts
- CVE-2026-98432 is a use-after-free in the Linux kernel's IPv4 TCP handshake path.[Hacker News]
- The Linux CNA record assigns CVSS 3.1 9.8, citing network reachability and no required privileges or user interaction.[Hacker News]
- Red Hat's public advisory and machine-readable record list a preliminary CVSS 3.1 score of 8.1.[Hacker News]
- Anthropic's Frontier Red Team reported remote root command execution against a server with a Multipath TCP listener in a controlled lab.[Hacker News]
- The upstream patch was merged as commit e3f33b0a1d89, which frees inet_opt and ireq_opt after an RCU grace period.[Hacker News]
What remains uncertain
- Severity scores differ across issuers, and Red Hat's 8.1 score is preliminary.[Hacker News]
- No authoritative source cited in the reporting establishes widespread exploitation across the public internet.[Hacker News]
- The remote root execution demonstration was carried out in a controlled lab under a specific configuration, not against all Linux TCP listeners.[Hacker News]
Sources
Outlet counts describe coverage, not independent confirmation. Reports may share a wire service or original source.