FKIE_CVE-2026-63952
Vulnerability from fkie_nvd - Published: 2026-07-19 16:17 - Updated: 2026-07-20 15:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
memfd: deny writeable mappings when implying SEAL_WRITE
When SEAL_EXEC is added, SEAL_WRITE is implied to make W^X. But the
implied seal is set after the check that makes sure the memfd can not have
any writable mappings. This means one can use SEAL_EXEC to apply
SEAL_WRITE while having writeable mappings.
This breaks the contract that SEAL_WRITE provides and can be used by an
attacker to pass a memfd that appears to be write sealed but can still be
modified arbitrarily.
Fix this by adding the implied seals before the call for
mapping_deny_writable() is done.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"mm/memfd.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "b3f4f82d1315f1439059a83d1c22c51a5b43d99e",
"status": "affected",
"version": "c4f75bc8bd6b3d62665e1f5400c419540edb5601",
"versionType": "git"
},
{
"lessThan": "3be2a24f7f72ad7321ed6ad1715b956a4527bcf4",
"status": "affected",
"version": "c4f75bc8bd6b3d62665e1f5400c419540edb5601",
"versionType": "git"
},
{
"lessThan": "0995d1f79aed8ccbf62056189dd53fd19726ea08",
"status": "affected",
"version": "c4f75bc8bd6b3d62665e1f5400c419540edb5601",
"versionType": "git"
},
{
"lessThan": "555702282d4536a865dfffb1cd4f6028f196e7e8",
"status": "affected",
"version": "c4f75bc8bd6b3d62665e1f5400c419540edb5601",
"versionType": "git"
},
{
"lessThan": "3b041514cb6eae45869b020f743c14d983363222",
"status": "affected",
"version": "c4f75bc8bd6b3d62665e1f5400c419540edb5601",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"mm/memfd.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.3"
},
{
"lessThan": "6.3",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.143",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.93",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.35",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.0.*",
"status": "unaffected",
"version": "7.0.12",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1",
"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\nmemfd: deny writeable mappings when implying SEAL_WRITE\n\nWhen SEAL_EXEC is added, SEAL_WRITE is implied to make W^X. But the\nimplied seal is set after the check that makes sure the memfd can not have\nany writable mappings. This means one can use SEAL_EXEC to apply\nSEAL_WRITE while having writeable mappings.\n\nThis breaks the contract that SEAL_WRITE provides and can be used by an\nattacker to pass a memfd that appears to be write sealed but can still be\nmodified arbitrarily.\n\nFix this by adding the implied seals before the call for\nmapping_deny_writable() is done."
}
],
"id": "CVE-2026-63952",
"lastModified": "2026-07-20T15:16:58.823",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "NONE",
"baseScore": 8.4,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.0,
"impactScore": 5.8,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-07-19T16:17:13.950",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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