Red Hat has released fixed kernels for Red Hat Enterprise Linux 8, 9 and 10 to address CVE-2026-98432, a critical use-after-free flaw in the Linux kernel’s IPv4 TCP code that can allow remote, unauthenticated code execution.
Red Hat now rates the vulnerability Critical with a CVSS 3.1 score of 9.8, matching the Linux kernel CVE team’s score. The flaw arises from a race condition during TCP connection processing, according to Red Hat’s security bulletin.
The fixed RHEL packages are kernel 4.18.0-553.182.1.el8_10 under RHSA-2026:93414, kernel 5.14.0-687.64.1.el9_8 under RHSA-2026:93412, and kernel 6.12.0-211.72.1.el10_2 under RHSA-2026:93413. The new kernel takes effect after a reboot.
Canonical said fixes for Ubuntu 22.04 LTS, 24.04 LTS and 26.04 LTS remain in the opt-in -proposed testing channel, with no date set for promotion to regular updates. The corresponding proposed kernel versions are 5.15.0-203.213, 6.8.0-149.149 and 7.0.0-43.43. Ubuntu 26.10 has a fix in 7.3.0-10.10, while older supported releases remain pending, according to Canonical’s November 2 update.
Anthropic previously described a proof-of-concept exploit for the same flaw that reached root on a Linux server with a Multipath TCP listener, as covered in Abijita’s report on Claude’s exploit research. The underlying vulnerability is in IPv4 TCP and is not specific to Multipath TCP.
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