{"id":"CVE-2026-99110","state":"PUBLISHED","title":"smb: client: fix heap overflow in cifs_do_set_acl()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix heap overflow in cifs_do_set_acl()\n\ncifs_set_acl() validates ACL size using posix_acl_xattr_size():\n\n        4 + (count * 8)  // 4-byte header + 8 bytes per ACE\n\ncifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS\nwire format into the same buffer:\n\n        6 + (count * 10)  // 6-byte header + 10 bytes per ACE\n\nAn ACL that passes the xattr-based check in cifs_set_acl() can\noverflow the heap when posix_acl_to_cifs() writes the larger CIFS\nformat.\n\nValidate the CIFS format size against the remaining buffer space and\nUSHRT_MAX before converting--data_count is __u16, so sizes above\nUSHRT_MAX truncate the on-wire packet length, causing the server to\napply a partial ACL.  Replace MaxDataCount = 1000 with\nmin(CIFSMaxBufSize, USHRT_MAX).","publishedAt":"2026-10-28T10:34:28.239Z","updatedAt":"2026-10-30T12:41:48.303Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"68652afb9b9adf70125971abee9b95341e042249","versionType":"git"},{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"9312a00215602ba028495ef3fa00fb84af0478e0","versionType":"git"},{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"d96f3365ce61c5f39602955af43c8174548dee98","versionType":"git"},{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"596b4062e6c75bdd85a7f2b7f2087a872dc420ac","versionType":"git"},{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"1dac61e2c29d1a71784604b48cf3b1234a65ec29","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/cifssmb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/cifssmb.c"]}],"references":["https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249","https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0","https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98","https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac","https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29"],"weaknesses":[],"ingestedAt":"2026-10-30T13:02:04.640Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99110.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99110","state":"PUBLISHED","datePublished":"2026-10-28T10:34:28.239Z","dateUpdated":"2026-10-30T12:41:48.303Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.392Z"},"containers":{"cna":{"title":"smb: client: fix heap overflow in cifs_do_set_acl()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix heap overflow in cifs_do_set_acl()\n\ncifs_set_acl() validates ACL size using posix_acl_xattr_size():\n\n        4 + (count * 8)  // 4-byte header + 8 bytes per ACE\n\ncifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS\nwire format into the same buffer:\n\n        6 + (count * 10)  // 6-byte header + 10 bytes per ACE\n\nAn ACL that passes the xattr-based check in cifs_set_acl() can\noverflow the heap when posix_acl_to_cifs() writes the larger CIFS\nformat.\n\nValidate the CIFS format size against the remaining buffer space and\nUSHRT_MAX before converting--data_count is __u16, so sizes above\nUSHRT_MAX truncate the on-wire packet length, causing the server to\napply a partial ACL.  Replace MaxDataCount = 1000 with\nmin(CIFSMaxBufSize, USHRT_MAX)."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"68652afb9b9adf70125971abee9b95341e042249","versionType":"git"},{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"9312a00215602ba028495ef3fa00fb84af0478e0","versionType":"git"},{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"d96f3365ce61c5f39602955af43c8174548dee98","versionType":"git"},{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"596b4062e6c75bdd85a7f2b7f2087a872dc420ac","versionType":"git"},{"version":"dc1af4c4b4721abfa07b351063825acc7e69cc66","status":"affected","lessThan":"1dac61e2c29d1a71784604b48cf3b1234a65ec29","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/cifssmb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/smb/client/cifssmb.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249"},{"url":"https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0"},{"url":"https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98"},{"url":"https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac"},{"url":"https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:41:48.303Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.161"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.12.115"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.18.59"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.2.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}