FKIE_CVE-2026-72237
Vulnerability from fkie_nvd - Published: 2026-08-15 06:21 - Updated: 2026-08-19 17:21
Severity
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.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/x86/events/amd/brs.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "4f949bc3913a6e3ce3b8574ac6ed1da8ec7a5ad1",
"status": "affected",
"version": "8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08",
"versionType": "git"
},
{
"lessThan": "ac44b4a3d6137489f8fa2e794b12e849c6b22eaa",
"status": "affected",
"version": "8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08",
"versionType": "git"
},
{
"lessThan": "90843d00dbc61220b66408ea0d8775cae9e51f70",
"status": "affected",
"version": "8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08",
"versionType": "git"
},
{
"lessThan": "046f6244da9b68e463a849b21446b9424e531491",
"status": "affected",
"version": "8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08",
"versionType": "git"
},
{
"lessThan": "2e706be56f418718bb3ae66c0aa94f9b61150e6d",
"status": "affected",
"version": "8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08",
"versionType": "git"
},
{
"lessThan": "47915e855fb38b42133e31ba917d99565f862154",
"status": "affected",
"version": "8910075d61a37e5b0d82e6c83ed9a0a31fe9ea08",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"arch/x86/events/amd/brs.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"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"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"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."
}
],
"id": "CVE-2026-72237",
"lastModified": "2026-08-19T17:21:00.693",
"metrics": {},
"published": "2026-08-15T06:21:50.733",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/046f6244da9b68e463a849b21446b9424e531491"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/2e706be56f418718bb3ae66c0aa94f9b61150e6d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/47915e855fb38b42133e31ba917d99565f862154"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4f949bc3913a6e3ce3b8574ac6ed1da8ec7a5ad1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/90843d00dbc61220b66408ea0d8775cae9e51f70"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ac44b4a3d6137489f8fa2e794b12e849c6b22eaa"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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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.
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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