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GHSA-WCFV-P978-69XF

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-19 18:32

Details

In the Linux kernel, the following vulnerability has been resolved:

perf/x86/amd/brs: 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_BRS (Zen 3 only), perf can still report entries such as SYSRET/interrupt returns for which the branch-from addresses are in the kernel.

E.g.

$ perf record -j any,u -c 4000 -e branch-brs -o - -- \ perf bench syscall basic --loop 1000 | \ perf script -i - -F brstack|tr ' ' '\n'| \ grep -E '0x[89a-f][0-9a-f]{15}'

... 0xffffffff810001c4/0x72e2e32955eb/-/-/-/0//- 0xffffffff810001c4/0x72e2d94a9821/-/-/-/0//- 0xffffffff810001c4/0x72e2d94ffa1b/-/-/-/0//- ...

BRS provides no hardware branch filtering, so privilege level filtering is performed entirely in software. However, amd_brs_match_plm() only validates the branch-to address against the requested privilege levels. For branches from the kernel to user space, the branch-from address is left unchecked and is leaked. Extend the software filter to also validate the branch-from address, so that any branch record whose branch-from address is in the kernel is dropped when PERF_SAMPLE_BRANCH_USER is requested.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72237"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:50Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/amd/brs: 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_BRS (Zen 3 only), perf can still report entries\nsuch as SYSRET/interrupt returns for which the branch-from addresses\nare in the kernel.\n\nE.g.\n\n  $ perf record -j any,u -c 4000 -e branch-brs -o - -- \\\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  0xffffffff810001c4/0x72e2e32955eb/-/-/-/0//-\n  0xffffffff810001c4/0x72e2d94a9821/-/-/-/0//-\n  0xffffffff810001c4/0x72e2d94ffa1b/-/-/-/0//-\n  ...\n\nBRS provides no hardware branch filtering, so privilege level\nfiltering is performed entirely in software. However, amd_brs_match_plm()\nonly validates the branch-to address against the requested privilege\nlevels. For branches from the kernel to user space, the branch-from\naddress is left unchecked and is leaked. Extend the software filter to\nalso validate the branch-from address, so that any branch record whose\nbranch-from address is in the kernel is dropped when\nPERF_SAMPLE_BRANCH_USER is requested.",
  "id": "GHSA-wcfv-p978-69xf",
  "modified": "2026-08-19T18:32:27Z",
  "published": "2026-08-15T06:32:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72237"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/046f6244da9b68e463a849b21446b9424e531491"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2e706be56f418718bb3ae66c0aa94f9b61150e6d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/47915e855fb38b42133e31ba917d99565f862154"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4f949bc3913a6e3ce3b8574ac6ed1da8ec7a5ad1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/90843d00dbc61220b66408ea0d8775cae9e51f70"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ac44b4a3d6137489f8fa2e794b12e849c6b22eaa"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-72237 (GCVE-0-2026-72237)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:54 – Updated: 2026-08-19 16:36

Title

perf/x86/amd/brs: Fix kernel address leakage

Summary

In the Linux kernel, the following vulnerability has been resolved: perf/x86/amd/brs: 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_BRS (Zen 3 only), perf can still report entries such as SYSRET/interrupt returns for which the branch-from addresses are in the kernel. E.g. $ perf record -j any,u -c 4000 -e branch-brs -o - -- \ perf bench syscall basic --loop 1000 | \ perf script -i - -F brstack|tr ' ' '\n'| \ grep -E '0x[89a-f][0-9a-f]{15}' ... 0xffffffff810001c4/0x72e2e32955eb/-/-/-/0//- 0xffffffff810001c4/0x72e2d94a9821/-/-/-/0//- 0xffffffff810001c4/0x72e2d94ffa1b/-/-/-/0//- ... BRS provides no hardware branch filtering, so privilege level filtering is performed entirely in software. However, amd_brs_match_plm() only validates the branch-to address against the requested privilege levels. For branches from the kernel to user space, the branch-from address is left unchecked and is leaked. Extend the software filter to also validate the branch-from address, so that any branch record whose branch-from address is in the kernel is dropped when PERF_SAMPLE_BRANCH_USER is requested.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

6 references

URL	Tags
https://git.kernel.org/stable/c/4f949bc3913a6e3ce…
https://git.kernel.org/stable/c/ac44b4a3d6137489f…
https://git.kernel.org/stable/c/90843d00dbc61220b…
https://git.kernel.org/stable/c/046f6244da9b68e46…
https://git.kernel.org/stable/c/2e706be56f418718b…
https://git.kernel.org/stable/c/47915e855fb38b421…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08 , < 4f949bc3913a6e3ce3b8574ac6ed1da8ec7a5ad1 (git) Affected: 8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08 , < ac44b4a3d6137489f8fa2e794b12e849c6b22eaa (git) Affected: 8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08 , < 90843d00dbc61220b66408ea0d8775cae9e51f70 (git) Affected: 8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08 , < 046f6244da9b68e463a849b21446b9424e531491 (git) Affected: 8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08 , < 2e706be56f418718bb3ae66c0aa94f9b61150e6d (git) Affected: 8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08 , < 47915e855fb38b42133e31ba917d99565f862154 (git)
Linux	Linux	Affected: 5.19 Unaffected: 0 , < 5.19 (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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JSON

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{
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/events/amd/brs.c"
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          "vendor": "Linux",
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          "versions": [
            {
              "status": "affected",
              "version": "5.19"
            },
            {
              "lessThan": "5.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "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:*:*:*:*:*:*:*:*",
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                },
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                },
                {
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/amd/brs: 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_BRS (Zen 3 only), perf can still report entries\nsuch as SYSRET/interrupt returns for which the branch-from addresses\nare in the kernel.\n\nE.g.\n\n  $ perf record -j any,u -c 4000 -e branch-brs -o - -- \\\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  0xffffffff810001c4/0x72e2e32955eb/-/-/-/0//-\n  0xffffffff810001c4/0x72e2d94a9821/-/-/-/0//-\n  0xffffffff810001c4/0x72e2d94ffa1b/-/-/-/0//-\n  ...\n\nBRS provides no hardware branch filtering, so privilege level\nfiltering is performed entirely in software. However, amd_brs_match_plm()\nonly validates the branch-to address against the requested privilege\nlevels. For branches from the kernel to user space, the branch-from\naddress is left unchecked and is leaked. Extend the software filter to\nalso validate the branch-from address, so that any branch record whose\nbranch-from address is in the kernel is dropped when\nPERF_SAMPLE_BRANCH_USER is requested."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:36:31.271Z",
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          "url": "https://git.kernel.org/stable/c/2e706be56f418718bb3ae66c0aa94f9b61150e6d"
        },
        {
          "url": "https://git.kernel.org/stable/c/47915e855fb38b42133e31ba917d99565f862154"
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      "title": "perf/x86/amd/brs: Fix kernel address leakage",
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    "cveId": "CVE-2026-72237",
    "datePublished": "2026-08-15T05:54:26.685Z",
    "dateReserved": "2026-08-09T03:40:39.914Z",
    "dateUpdated": "2026-08-19T16:36:31.271Z",
    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-WCFV-P978-69XF

CVE-2026-72237 (GCVE-0-2026-72237)

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