Linux Kernel IPv4 TCP Use-After-Free
A race in IPv4 TCP connection handling can leave freed socket options in use. Anthropic demonstrated remote root execution on an MPTCP listener.
- Vendor
- Linux
- Product
- Linux kernel
- CVSS
- 9.8
- EPSS (exploit probability)
- N/A
- Status
- patched
- Published
Is CVE-2026-98432 being exploited?
Not on any exploited-vulnerability catalog we track. CVE-2026-98432 was not on the CISA, ENISA or CIRCL exploited catalogs as of our 2026-10-31 snapshot. That can change quickly; check the write-up below for the latest reporting.
- CISA KEV[ — ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-10-31. Full cross-catalog view: /kev-comparison
CVE-2026-98432 timeline
Every event links to its source. Catalog dates are each catalog's own; day offsets count from NVD publication. Data: JSON
The Linux kernel CVE record identifies a use-after-free race in IPv4 TCP connection processing and assigns CVSS 3.1 9.8 (Critical). It lists upstream and stable-branch fixes. Distribution kernel packages need separate verification.
Anthropic reports a demonstrated unauthenticated remote root exploit against a server with an MPTCP listener. This is a research demonstration; the cited sources do not establish exploitation in the wild. The Go Security Team says the underlying flaw is not limited to MPTCP and recommends upgrading to a patched kernel.
Check your distribution’s Ubuntu, Debian, Red Hat, or CIQ advisory for package status, then install the fixed kernel and reboot. Upstream patch availability alone does not establish that a running distribution kernel is fixed.
Other Linux Kernel CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2026-46300 Linux Kernel Missing Initialization of a Variable Vulnerability | [ HIGH ] | 7.8 | 16.1% | |
| CVE-2026-53266 Linux Kernel Out-of-Bounds Write Vulnerabilitywrite-up | [ HIGH ] | 8.8 | 0.9% | |
| CVE-2025-39964 Linux Kernel Race Condition Vulnerabilitywrite-up | [ HIGH ] | 7.8 | 1.6% | |
| CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Vulnerabilitywrite-up | [ CRITICAL ] | 9.8 | 3.3% | |
| CVE-2026-53362 Linux Kernel Unspecified Vulnerability | [ HIGH ] | 7.8 | 0.7% | |
| CVE-2022-0995 Linux Kernel Out-of-Bounds Write Vulnerability | [ HIGH ] | 7.8 | 8.9% | |
| CVE-2026-53264 Linux kernel traffic-control subsystem use-after-free racewrite-up | [ HIGH ] | 7.8 | 0.5% | — |
| CVE-2022-0492 Linux Kernel Improper Authentication Vulnerability | [ HIGH ] | 7.8 | 5.5% |
