CVE-2026-90111

A flaw was found in the Linux kernel's IPv6 multicast routing (ip6mr) component. This use-after-free vulnerability occurs when a non-refcounted destination entry is improperly handled after being freed. A remote attacker could potentially exploit this by sending specially crafted IPv6 multicast packets, leading to system instability, denial of service, or potentially arbitrary code execution.

This vulnerability is rated as Important because an authenticated local attacker could leverage the memory corruption flaw to compromise kernel integrity or cause a system crash, escalating privileges beyond normal boundaries. Standard Red Hat Enterprise Linux deployments do not enable IPv6 multicast routing by default, which significantly reduces exposure for typical server installations. The risk is primarily relevant to systems specifically acting as IPv6 multicast routers or environments permitting unprivileged user namespaces where network administration capabilities can be obtained.

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.