CVE-2026-80602

A flaw was found in the Linux kernel's perf subsystem. This vulnerability allows a local user to gain access to sensitive kernel memory addresses. This occurs because the system's branch stack, intended for user-only information, can inadvertently include kernel addresses, leading to an information disclosure.

A moderate information disclosure flaw was found in the Linux kernel's perf subsystem on AMD processors that support Last Branch Record Extension v2 (X86_FEATURE_AMD_LBR_V2). When perf requests a user-only branch stack (PERF_SAMPLE_BRANCH_USER), the AMD LBR v2 hardware filter only validates the privilege level of the branch target, so branch records such as SYSRET/ERET whose branch-from addresses lie in the kernel can still be reported to user space. A local user with access to perf branch sampling can therefore obtain kernel addresses, which weakens KASLR and other address-hiding defenses and can aid further local exploitation. The issue affects only the confidentiality of kernel address information; there is no direct impact on integrity or availability. Red Hat Enterprise Linux 8, 9, and 10 and Red Hat In-Vehicle OS kernel streams that contain the LbrExtV2 hardware branch filter support are affected, while streams that do not contain the vulnerable code (RHEL 6, RHEL 7, RHEL 8.4, RHEL 8.6, RHEL 8.8, and RHEL 9.2) are not affected. The fix is currently deferred for the affected streams and is expected to be delivered in a future scheduled kernel update rather than an immediate update; until it is applied, the residual risk on systems using affected AMD processors is limited to a local user, who is already able to use perf, disclosing kernel addresses.

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.