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CVE-2026-99083

ksmbd: fix heap out-of-bounds write in krb5_authenticate() PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix heap out-of-bounds write in krb5_authenticate() In krb5_authenticate(), out_len is calculated to determine available headroom in response_buf for the incoming Kerberos AP-REP token. However, when SMB2_SESSION_SETUP is processed as a non-first element of a compounded SMB2 request, the calculation omits work->next_smb2_rsp_hdr_off. This causes out_len to overstate remaining buffer headroom by the cumulative size of prior responses in the compound chain. Consequently, the length check in ksmbd_krb5_authenticate() (*out_len <= resp->spnego_blob_len) passes erroneously, allowing memcpy() to write the AP-REP blob past the end of response_buf into adjacent kernel heap memory. Fix this by subtracting work->next_smb2_rsp_hdr_off when computing out_len, ensuring it accurately reflects physical remaining buffer space.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 59c6dcc5dd9dafe764ca0d40525933b2be69b059; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 80af1bde97d5a85ad6f2c40ca894ccc8fa75a27a; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 517404e157395d0f8da125ca956c566895dfcd06; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 4722d06b2907585074252061b1024a696c1cfc23; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 23a0be6a84a38ac169eeab49017934e8e27c65f0; affected 0 before 6.6.160; affected 0 before 6.12.114; affected 0 before 6.18.58; affected 0 before 7.2.12
Linux / Linuxunaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.58 through 6.18.*; unaffected 7.2.12 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References