{"api_version":"1","generated_at":"2026-07-20T18:14:50+00:00","cve":"CVE-2026-63952","urls":{"html":"https://cve.report/CVE-2026-63952","api":"https://cve.report/api/cve/CVE-2026-63952.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63952","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63952"},"summary":{"title":"memfd: deny writeable mappings when implying SEAL_WRITE","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:13","updated_at":"2026-07-20 15:16:58"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.4","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","baseScore":8.4,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.4","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","data":{"baseScore":8.4,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222","name":"https://git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8","name":"https://git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e","name":"https://git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4","name":"https://git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08","name":"https://git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63952","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63952","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 b3f4f82d1315f1439059a83d1c22c51a5b43d99e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 3be2a24f7f72ad7321ed6ad1715b956a4527bcf4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 0995d1f79aed8ccbf62056189dd53fd19726ea08 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c4f75bc8bd6b3d62665e1f5400c419540edb5601 555702282d4536a865dfffb1cd4f6028f196e7e8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"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"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.143","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.93","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.35","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.12","versionStartIncluding":"6.3","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"6.3","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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."}],"metrics":[{"cvssV3_1":{"baseScore":8.4,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-20T13:41:51.115Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e"},{"url":"https://git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4"},{"url":"https://git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08"},{"url":"https://git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8"},{"url":"https://git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222"}],"title":"memfd: deny writeable mappings when implying SEAL_WRITE","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63952","datePublished":"2026-07-19T14:55:44.809Z","dateReserved":"2026-07-19T07:54:57.023Z","dateUpdated":"2026-07-20T13:41:51.115Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:13","lastModifiedDate":"2026-07-20 15:16:58","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","baseScore":8.4,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"NONE"},"exploitabilityScore":2,"impactScore":5.8}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"63952","Ordinal":"1","Title":"memfd: deny writeable mappings when implying SEAL_WRITE","CVE":"CVE-2026-63952","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63952","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"memfd: deny writeable mappings when implying SEAL_WRITE"}]}}}