{"id":"CVE-2026-31704","state":"PUBLISHED","title":"ksmbd: use check_add_overflow() to prevent u16 DACL size overflow","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use check_add_overflow() to prevent u16 DACL size overflow\n\nset_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes\nin u16 variables. When a file has many POSIX ACL entries, the\naccumulated size can wrap past 65535, causing the pointer arithmetic\n(char *)pndace + *size to land within already-written ACEs. Subsequent\nwrites then overwrite earlier entries, and pndacl->size gets a\ntruncated value.\n\nUse check_add_overflow() at each accumulation point to detect the\nwrap before it corrupts the buffer, consistent with existing\ncheck_mul_overflow() usage elsewhere in smbacl.c.","publishedAt":"2026-05-01T13:56:03.243Z","updatedAt":"2026-10-15T01:18:01.953Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"41e53a773db6342ac9a689ee5ba635c31744c9f0","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"8d5729350b236896f51379588d9a690b7fafb8db","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"e1955a94b6f17f4b058afa955a6f187eb3ed7615","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"299f962c0b02d048fb45d248b4da493d03f3175d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.136","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.84","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.25","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.2","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"]}],"references":["https://git.kernel.org/stable/c/41e53a773db6342ac9a689ee5ba635c31744c9f0","https://git.kernel.org/stable/c/8d5729350b236896f51379588d9a690b7fafb8db","https://git.kernel.org/stable/c/e1955a94b6f17f4b058afa955a6f187eb3ed7615","https://git.kernel.org/stable/c/5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43","https://git.kernel.org/stable/c/ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7","https://git.kernel.org/stable/c/299f962c0b02d048fb45d248b4da493d03f3175d","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31704.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31704","state":"PUBLISHED","datePublished":"2026-05-01T13:56:03.243Z","dateUpdated":"2026-10-15T01:18:01.953Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.132Z"},"containers":{"cna":{"title":"ksmbd: use check_add_overflow() to prevent u16 DACL size overflow","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use check_add_overflow() to prevent u16 DACL size overflow\n\nset_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes\nin u16 variables. When a file has many POSIX ACL entries, the\naccumulated size can wrap past 65535, causing the pointer arithmetic\n(char *)pndace + *size to land within already-written ACEs. Subsequent\nwrites then overwrite earlier entries, and pndacl->size gets a\ntruncated value.\n\nUse check_add_overflow() at each accumulation point to detect the\nwrap before it corrupts the buffer, consistent with existing\ncheck_mul_overflow() usage elsewhere in smbacl.c."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"41e53a773db6342ac9a689ee5ba635c31744c9f0","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"8d5729350b236896f51379588d9a690b7fafb8db","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"e1955a94b6f17f4b058afa955a6f187eb3ed7615","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7","versionType":"git"},{"version":"e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9","status":"affected","lessThan":"299f962c0b02d048fb45d248b4da493d03f3175d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.136","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.84","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.25","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.2","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/server/smbacl.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/41e53a773db6342ac9a689ee5ba635c31744c9f0"},{"url":"https://git.kernel.org/stable/c/8d5729350b236896f51379588d9a690b7fafb8db"},{"url":"https://git.kernel.org/stable/c/e1955a94b6f17f4b058afa955a6f187eb3ed7615"},{"url":"https://git.kernel.org/stable/c/5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43"},{"url":"https://git.kernel.org/stable/c/ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7"},{"url":"https://git.kernel.org/stable/c/299f962c0b02d048fb45d248b4da493d03f3175d"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-06-14T17:43:49.042Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.6.136"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.12.84"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.18.25"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"7.0.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","defaultStatus":"unknown","versions":[{"version":"0","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T01:18:01.953Z"},"x_adpType":"supplier"}]}}}