CVE-2026-64553

A flaw was found in the Linux kernel's packet sampling (psample) network module. This vulnerability, specifically within the PSAMPLE_ATTR_DATA attribute handling, occurs because the nla_put() function does not properly clear padding bytes. When the data length is not a multiple of four bytes, uninitialized memory from the kernel can be exposed. A local attacker could exploit this information leak to potentially gain access to sensitive data.

This vulnerability is rated as having Moderate impact for Red Hat Enterprise Linux because exploitation requires local access and is constrained to an uninitialized kernel memory disclosure of alignment padding bytes. Packet sampling through the psample module is not active by default and requires explicit system configuration, such as designated traffic control (tc) rules or Open vSwitch monitoring. Consequently, an unprivileged local user can only observe residual memory fragments if packet sampling is actively transmitting packets, limiting the overall confidentiality exposure without threatening system integrity or availability.

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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.