CVE-2026-80602 (GCVE-0-2026-80602)
Vulnerability from cvelistv5
Published
2026-08-28 06:48
Modified
2026-08-28 06:48
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: perf/x86/amd/lbr: Fix kernel address leakage A user-only branch stack can contain branches that originate from the kernel. As a result, kernel addresses are exposed to user space even when PERF_SAMPLE_BRANCH_USER is requested. On AMD processors supporting X86_FEATURE_AMD_LBR_V2, perf can still report SYSRET/ERET entries for which the branch-from addresses are in the kernel. E.g. $ perf record -e cycles -o - -j any,save_type,u -- \ perf bench syscall basic --loop 1000 | \ perf script -i - -F brstack|tr ' ' '\n'| \ grep -E '0x[89a-f][0-9a-f]{15}' ... 0xffffffff81001268/0x717a90a38f1a/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH 0xffffffff81001268/0x717a90a39157/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH 0xffffffff81001268/0x717a90a2c628/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH 0xffffffff81001268/0x717a90a41b60/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH 0xffffffff81001268/0x717a90a260db/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH 0xffffffff81001268/0x717a90a260db/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH 0xffffffff81001268/0x717a8bef1c30/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH 0xffffffff81001268/0x717a8e4d3c90/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH ... The reason is that the hardware filter only considers the privilege level applicable to the branch target. Extend software filtering to also validate the branch-from addresses against br_sel, so that any branch record whose branch-from address is in the kernel is dropped when PERF_SAMPLE_BRANCH_USER is requested.
References
Impacted products
Vendor Product Version
Linux Linux Version: f4f925dae7419fc7a10af539c073871927ce3a24
Version: f4f925dae7419fc7a10af539c073871927ce3a24
Version: f4f925dae7419fc7a10af539c073871927ce3a24
Version: f4f925dae7419fc7a10af539c073871927ce3a24
Version: f4f925dae7419fc7a10af539c073871927ce3a24
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/events/amd/lbr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5be478c1e08981ca91b34de310d7e2638171d9d8",
              "status": "affected",
              "version": "f4f925dae7419fc7a10af539c073871927ce3a24",
              "versionType": "git"
            },
            {
              "lessThan": "208ecca408b1707ad86ea247d3d3e09d3606fc13",
              "status": "affected",
              "version": "f4f925dae7419fc7a10af539c073871927ce3a24",
              "versionType": "git"
            },
            {
              "lessThan": "5ab0eba9c8819506bcb72348fd701f8a9006f95e",
              "status": "affected",
              "version": "f4f925dae7419fc7a10af539c073871927ce3a24",
              "versionType": "git"
            },
            {
              "lessThan": "fb3b76b5ad2ebad63dd76f8b65b624eaf638b73f",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "2a892294b83f541115c94b0bb637f39bef187657",
              "status": "affected",
              "version": "f4f925dae7419fc7a10af539c073871927ce3a24",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/events/amd/lbr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.1"
            },
            {
              "lessThan": "6.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/amd/lbr: Fix kernel address leakage\n\nA user-only branch stack can contain branches that originate from\nthe kernel. As a result, kernel addresses are exposed to user space\neven when PERF_SAMPLE_BRANCH_USER is requested. On AMD processors\nsupporting X86_FEATURE_AMD_LBR_V2, perf can still report SYSRET/ERET\nentries for which the branch-from addresses are in the kernel.\n\nE.g.\n\n  $ perf record -e cycles -o - -j any,save_type,u -- \\\n        perf bench syscall basic --loop 1000 | \\\n        perf script -i - -F brstack|tr \u0027 \u0027 \u0027\\n\u0027| \\\n        grep -E \u00270x[89a-f][0-9a-f]{15}\u0027\n\n  ...\n  0xffffffff81001268/0x717a90a38f1a/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH\n  0xffffffff81001268/0x717a90a39157/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH\n  0xffffffff81001268/0x717a90a2c628/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH\n  0xffffffff81001268/0x717a90a41b60/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH\n  0xffffffff81001268/0x717a90a260db/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH\n  0xffffffff81001268/0x717a90a260db/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH\n  0xffffffff81001268/0x717a8bef1c30/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH\n  0xffffffff81001268/0x717a8e4d3c90/M/-/-/0/ERET/NON_SPEC_CORRECT_PATH\n  ...\n\nThe reason is that the hardware filter only considers the privilege\nlevel applicable to the branch target. Extend software filtering to\nalso validate the branch-from addresses against br_sel, so that any\nbranch record whose branch-from address is in the kernel is dropped\nwhen PERF_SAMPLE_BRANCH_USER is requested."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-28T06:48:28.553Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5be478c1e08981ca91b34de310d7e2638171d9d8"
        },
        {
          "url": "https://git.kernel.org/stable/c/208ecca408b1707ad86ea247d3d3e09d3606fc13"
        },
        {
          "url": "https://git.kernel.org/stable/c/5ab0eba9c8819506bcb72348fd701f8a9006f95e"
        },
        {
          "url": "https://git.kernel.org/stable/c/fb3b76b5ad2ebad63dd76f8b65b624eaf638b73f"
        },
        {
          "url": "https://git.kernel.org/stable/c/2a892294b83f541115c94b0bb637f39bef187657"
        }
      ],
      "title": "perf/x86/amd/lbr: Fix kernel address leakage",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80602",
    "datePublished": "2026-08-28T06:48:28.553Z",
    "dateReserved": "2026-08-26T14:34:25.771Z",
    "dateUpdated": "2026-08-28T06:48:28.553Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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