{"id":"CVE-2026-99083","title":"ksmbd: fix heap out-of-bounds write in krb5_authenticate()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix heap out-of-bounds write in krb5_authenticate()\n\nIn krb5_authenticate(), out_len is calculated to determine available\nheadroom in response_buf for the incomi…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 59c6dcc5dd9dafe764ca0d40525933b2be69b059","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 80af1bde97d5a85ad6f2c40ca894ccc8fa75a27a","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 517404e157395d0f8da125ca956c566895dfcd06","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4722d06b2907585074252061b1024a696c1cfc23","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 23a0be6a84a38ac169eeab49017934e8e27c65f0","Linux < 6.6.160","Linux < 6.12.114","Linux < 6.18.58","Linux < 7.2.12","Linux (all versions)"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:45:01.735Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99083","references":[{"url":"https://git.kernel.org/stable/c/59c6dcc5dd9dafe764ca0d40525933b2be69b059"},{"url":"https://git.kernel.org/stable/c/80af1bde97d5a85ad6f2c40ca894ccc8fa75a27a"},{"url":"https://git.kernel.org/stable/c/517404e157395d0f8da125ca956c566895dfcd06"},{"url":"https://git.kernel.org/stable/c/4722d06b2907585074252061b1024a696c1cfc23"},{"url":"https://git.kernel.org/stable/c/23a0be6a84a38ac169eeab49017934e8e27c65f0"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.512Z","slug":"CVE-2026-99083","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix heap out-of-bounds write in krb5_authenticate()\n\nIn krb5_authenticate(), out_len is calculated to determine available\nheadroom in response_buf for the incoming Kerberos AP-REP token. However,\nwhen SMB2_SESSION_SETUP is processed as a non-first element of a compounded\nSMB2 request, the calculation omits work->next_smb2_rsp_hdr_off.\n\nThis causes out_len to overstate remaining buffer headroom by\nthe cumulative size of prior responses in the compound chain. Consequently,\nthe length check in ksmbd_krb5_authenticate()\n(*out_len <= resp->spnego_blob_len) passes erroneously, allowing memcpy()\nto write the AP-REP blob past the end of response_buf into adjacent kernel\nheap memory.\n\nFix this by subtracting work->next_smb2_rsp_hdr_off when computing out_len,\nensuring it accurately reflects physical remaining buffer space.\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 59c6dcc5dd9dafe764ca0d40525933b2be69b059`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 80af1bde97d5a85ad6f2c40ca894ccc8fa75a27a`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 517404e157395d0f8da125ca956c566895dfcd06`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4722d06b2907585074252061b1024a696c1cfc23`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 23a0be6a84a38ac169eeab49017934e8e27c65f0`\n- `Linux < 6.6.160`\n- `Linux < 6.12.114`\n- `Linux < 6.18.58`\n- `Linux < 7.2.12`\n- `Linux (all versions)`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}