CVE-2026-72433

A flaw was found in the Linux kernel's netfilter component, specifically within the nft_meta_bridge module. This vulnerability, a stack leak, occurs due to improper handling of return values, which fails to test for nonzero results. An attacker could potentially exploit this issue to gain access to sensitive information from the kernel's memory.

A moderate information disclosure flaw was found in the Linux kernel's bridge netfilter implementation (nft_meta_bridge) in Red Hat Enterprise Linux 9 and 10. When the NFT_META_BRI_IIFPVID meta expression is evaluated, the return value of br_vlan_get_pvid_rcu() is not tested for a nonzero result before the stack variable holding the bridge ingress port VLAN ID is copied into an nftables register, which can leak an uninitialized kernel stack value. A local attacker with the privileges required to configure nftables rules (CAP_NET_ADMIN) could observe this leaked kernel stack data through rule evaluation, resulting in limited exposure of kernel memory contents.

In Red Hat Enterprise Linux, the kernel and kernel-rt packages in RHEL 6, 7, and 8, and the Red Hat In-Vehicle OS kernel components, are not affected because the vulnerable code is not present in those builds. The affected RHEL 9 and RHEL 10 kernel and kernel-rt streams are assessed as affected with the fix deferred: exploiting this flaw requires local privileged access to configure nftables rules and its consequence is limited to leaking a small amount of kernel stack data, so the residual risk of postponing the fix is considered low.

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.