This Red Hat security advisory (RHSA-2026:27713) addresses eight kernel vulnerabilities in Red Hat Enterprise Linux 9.4. The issues fixed include: a zero-length check in netfilter's nf_conntrack_h323 DecodeQ931() (CVE-2026-23455); a slab-use-after-free in mptcp's __inet_lookup_established (CVE-2026-31669); a double dma_buf_unpin in RDMA/umem failure path (CVE-2026-43128); strict checking of maximum actions in netfilter flowtable (CVE-2026-43329); extension of writable skb range in net/sched act_pedit (CVE-2026-46331); reservation of mac_len headroom in ipv6 rpl when recompressed SRH grows (CVE-2026-43501); a double free in RDMA/rxe rxe_srq_from_init (CVE-2026-45852); and prevention of preemption of oopsing TASK_DEAD task on exit (CVE-2026-46173). The advisory also includes bug fixes and enhancements related to recursive locking detection. The update requires a system reboot to take effect.

The vulnerabilities fixed in this advisory affect core kernel components and could lead to memory corruption issues such as use-after-free and double free, potentially causing system instability or denial of service. Improper input validation and preemption handling could also lead to unexpected kernel behavior. The advisory rates the overall security impact as Important (high severity). No known exploits in the wild have been reported at this time.

Red Hat has released updated kernel packages for Red Hat Enterprise Linux 9.4 that address these vulnerabilities. Users should apply the update promptly by following Red Hat's update instructions and reboot their systems to ensure the fixes take effect. Refer to the official Red Hat advisory RHSA-2026:27713 and the article https://access.redhat.com/articles/11258 for detailed update procedures.