smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr() reparse_buf_ptr() reads buf->ReparseDataLength before checking that count covers the full fixed header: buf = (struct reparse_data_buffer *)((u8 *)io + off); len = sizeof(*buf); /* 8 bytes */ rdlen = le16_to_cpu(buf->ReparseDataLength); /* offset 4, 2 bytes */ if (count < len || count < rdlen + len) /* check comes after */ struct reparse_data_buffer has ReparseDataLength at offset 4. If a server returns OutputCount < 6, the read at offset 4-5 reaches past the end of the received data. The off+count bounds against iov_len were already validated, but that does not protect against count being smaller than sizeof(*buf). Split the check: verify count >= sizeof(*buf) before reading ReparseDataLength, then verify count covers the data region.
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 6.6.160, 7.2.4
- CVEs
- CVE-2026-89632
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 15:00 UTC · Revision 1
Source evidence
smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr()
core-osv · Original sourcePublished 11 Sept 2026, 19:45 UTC
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix use-before-check of ReparseDataLength in reparse_buf_ptr() reparse_buf_ptr() reads buf->ReparseDataLength before checking that count covers the full fixed header: buf = (struct reparse_data_buffer *)((u8 *)io + off); len = sizeof(*buf); /* 8 bytes */ rdlen = le16_to_cpu(buf->ReparseDataLength); /* offset 4, 2 bytes */ if (count < len || count < rdlen + len) /* check comes after */ struct reparse_data_buffer has ReparseDataLength at offset 4. If a server returns OutputCount < 6, the read at offset 4-5 reaches past the end of the received data. The off+count bounds against iov_len were already validated, but that does not protect against count being smaller than sizeof(*buf). Split the check: verify count >= sizeof(*buf) before reading ReparseDataLength, then verify count covers the data region.
osv:CVE-2026-89632
Kernel
Fixed versions: 6.6.160, 7.2.4
Complete source record
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"modified": "2026-10-28T02:30:36.555393286Z",
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