{
  "id": 17490807,
  "title": "TCP Use-After-Free: CVE-2026-98432 / CVSS 9.8",
  "url": "https://urgent.news/2026/10/31/tcp-use-after-free-cve-2026-98432-cvss-9-8-17490807",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-10-31T19:16:30.000Z",
  "source": {
    "name": "Hacker News Best",
    "slug": "hacker-news-best",
    "url": "https://atlasum.net/blog/cve-2026-98432-linux-ipv4-tcp-uaf"
  },
  "original_language": "en",
  "account": "A critical use-after-free vulnerability, CVE-2026-98432, affects Linux TCP handshakes. This flaw allows a remote, unauthenticated adversary to overflow kernel memory, potentially leading to system crashes or unauthorized command execution. The vulnerability, present since Linux 4.4, has been fixed in various kernel versions ranging from 5.10.272 to 7.3. However, many servers still run outdated distributions that have not applied the fix. Ubuntu users, for instance, are still flagged as vulnerable despite a fix being available. The bug's severity is underscored by Anthropic's demonstration of a proof-of-concept exploit that could run commands as root on affected systems. The fix involves a four-line change to the kernel, which prevents the premature freeing of TCP options before the handshake is complete. Distributions like Red Hat have elevated the severity of the bug to Critical (9.8) due to the minimal prerequisites required for exploitation and the potential for severe system instability. Immediate updates and reboots are recommended to mitigate the risk.",
  "summary": "CVE-2026-98432 is a critical use-after-free vulnerability in the Linux TCP handshake handling code, which affects a wide range of Linux distributions and versions. The flaw allows a remote, unauthenticated attacker to exploit the kernel's handling of IPv4 TCP connection requests, potentially leading to unauthorized command execution or system instability. The bug exists in the kernel since version 4.4 and persists in most distributions, including Ubuntu and Red Hat Enterprise Linux (RHEL). The vulnerability is particularly dangerous as it can be exploited without any authentication or credentials, and the CNA has rated it with a CVSS score of 9.8, indicating its high severity. Red Hat recently increased the severity rating to Critical, emphasizing the potential for severe system instability. Linux servers running the unpatched kernel are at risk, as well as any containerized environments that rely on the host's kernel.",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}