Linux kernel TCP use-after-free published as CVE-2026-98432
Original title: Linux Kernel TCP Flaw (CVE-2026-98432)
Okta says its environments are patched or mitigated and it has seen no exploitation.
On October 25, 2026, the National Vulnerability Database published CVE-2026-98432, a use-after-free in the Linux kernel IPv4 TCP stack. Handling a retransmitted SYN can read already-freed IP options, which can crash the system or corrupt memory. The fix defers freeing those options until after an RCU grace period. Okta says Okta and Auth0 environments are patched or mitigated.
Unconfirmed: Affected kernel versions and a specific fixed kernel version are not stated.
- Okta has observed no evidence of exploitation to date.
- Access Gateway customers should upgrade to the latest version and restart the appliance.
- The kernel waits for an RCU grace period before releasing the IP options.
Impact: Crash or memory corruption in the kernel TCP stack
| Product | Affected | Fixed in |
|---|---|---|
| Linux kernel | — | — |
| Okta Access Gateway | — | latest version |
- 1.Upgrade Okta Access Gateway to the latest version and restart the appliance.
- CVEs
- CVE-2026-98432
- Organizations
- National Vulnerability Database
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2026-98432 | Use-after-free in Linux kernel IPv4 TCP options | 9.8 | <1% | PoC ×25 |
From the original article
1 min read at sec.okta.com
What happened? On October 25, 2026, the National Vulnerability Database published CVE-2026-98432, a vulnerability in the Linux kernel's IPv4 TCP stack. The flaw is a use-after-free: when a server handles a retransmitted SYN for a connection request, ...
sec.okta.com
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