CVE-2026-97597

A flaw was found in the Linux kernel's IPv6 (Internet Protocol version 6) subsystem. A local unprivileged user can cause a Denial of Service (DoS) by repeatedly requesting leases for a shared network flow label. Because the kernel fails to enforce per-socket lease limits during label reuse, memory is allocated without restriction, potentially exhausting system resources and causing the host to crash.

A low impact denial of service flaw was found in the Linux kernel's IPv6 flow label handling, affecting Red Hat Enterprise Linux (kernel and kernel-rt), Red Hat In-Vehicle OS, and the OpenShift Container Platform RHEL CoreOS kernel. The ipv6_flowlabel_get() function allocates an ipv6_fl_socklist lease entry for every successful flow label request, and the recheck path for an existing shareable flow label does not apply a per-socket lease admission check. A local unprivileged attacker could exploit this by repeatedly requesting leases for the same shareable IPv6 flow label, growing the socket's lease list and kernel memory consumption without bound, potentially causing memory exhaustion and crashing the host. Confidentiality and integrity are not affected.

Red Hat Product Security rates the impact of this issue as Low because exploitation requires local access with authenticated user privileges and only system availability is impacted; this differs from the upstream CVSS:3.1 base score of 5.5 (Moderate), which reflects the availability-only impact of local memory exhaustion. Fixes for the affected streams are currently deferred, so the residual risk of a local denial of service remains until a fix is delivered; the Red Hat Enterprise Linux 6 stream is out of support scope and will not receive a fix.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.