CVE-2026-80602

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> perf/x86/amd/lbr: Fix kernel address leakage<br /> <br /> A user-only branch stack can contain branches that originate from<br /> the kernel. As a result, kernel addresses are exposed to user space<br /> even when PERF_SAMPLE_BRANCH_USER is requested. On AMD processors<br /> supporting X86_FEATURE_AMD_LBR_V2, perf can still report SYSRET/ERET<br /> entries for which the branch-from addresses are in the kernel.<br /> <br /> E.g.<br /> <br /> $ perf record -e cycles -o - -j any,save_type,u -- \<br /> perf bench syscall basic --loop 1000 | \<br /> perf script -i - -F brstack|tr &amp;#39; &amp;#39; &amp;#39;\n&amp;#39;| \<br /> grep -E &amp;#39;0x[89a-f][0-9a-f]{15}&amp;#39;<br /> <br /> ...<br /> 0xffffffff81001268/0x717a90a38f1a/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH<br /> 0xffffffff81001268/0x717a90a39157/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH<br /> 0xffffffff81001268/0x717a90a2c628/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH<br /> 0xffffffff81001268/0x717a90a41b60/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH<br /> 0xffffffff81001268/0x717a90a260db/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH<br /> 0xffffffff81001268/0x717a90a260db/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH<br /> 0xffffffff81001268/0x717a8bef1c30/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH<br /> 0xffffffff81001268/0x717a8e4d3c90/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH<br /> ...<br /> <br /> The reason is that the hardware filter only considers the privilege<br /> level applicable to the branch target. Extend software filtering to<br /> also validate the branch-from addresses against br_sel, so that any<br /> branch record whose branch-from address is in the kernel is dropped<br /> when PERF_SAMPLE_BRANCH_USER is requested.