{"id":"CVE-2026-63952","revision":"4d72d2573bf7477bbf7d4e8d334f2b1c","records":[{"revision":"4d72d2573bf7477bbf7d4e8d334f2b1c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-63952","aliases":[],"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":0,"publishedAt":"2026-07-19T14:55:44.809+00:00","modifiedAt":"2026-10-19T20:17:59.011+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"mm/memfd.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"c4f75bc8bd6b3d62665e1f5400c419540edb5601\",\n                            \"lessThan\": \"b3f4f82d1315f1439059a83d1c22c51a5b43d99e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c4f75bc8bd6b3d62665e1f5400c419540edb5601\",\n                            \"lessThan\": \"3be2a24f7f72ad7321ed6ad1715b956a4527bcf4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c4f75bc8bd6b3d62665e1f5400c419540edb5601\",\n                            \"lessThan\": \"0995d1f79aed8ccbf62056189dd53fd19726ea08\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c4f75bc8bd6b3d62665e1f5400c419540edb5601\",\n                            \"lessThan\": \"555702282d4536a865dfffb1cd4f6028f196e7e8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"c4f75bc8bd6b3d62665e1f5400c419540edb5601\",\n                            \"lessThan\": \"3b041514cb6eae45869b020f743c14d983363222\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"mm/memfd.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.3\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.3\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.143\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.93\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.35\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0.12\",\n                            \"lessThanOrEqual\": \"7.0.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N","score":8.4,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/b3f4f82d1315f1439059a83d1c22c51a5b43d99e","https://git.kernel.org/stable/c/3be2a24f7f72ad7321ed6ad1715b956a4527bcf4","https://git.kernel.org/stable/c/0995d1f79aed8ccbf62056189dd53fd19726ea08","https://git.kernel.org/stable/c/555702282d4536a865dfffb1cd4f6028f196e7e8","https://git.kernel.org/stable/c/3b041514cb6eae45869b020f743c14d983363222"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63952","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-63952","identifiers":["CVE-2026-63952"]},"retained":false,"historicalAffected":[]}],"coverage":[]}