In the Linux kernel, the following vulnerability has been resolved:
NFSv4.2: Rework scratch handling for READ_PLUS (again)
I found that the read code might send multiple requests using the same nfs_pgio_header, but nfs4_proc_read_setup() is only called once. This is how we ended up occasionally double-freeing the scratch buffer, but also means we set a NULL pointer but non-zero length to the xdr scratch buffer. This results in an oops the first time decoding needs to copy something to scratch, which frequently happens when decoding READ_PLUS hole segments.
I fix this by moving scratch handling into the pageio read code. I provide a function to allocate scratch space for decoding read replies, and free the scratch buffer when the nfs_pgio_header is freed.
CVSS Details
- CVSS 3.1 Base Score: 9.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Sep 19, 2025 | Sep 19, 2025 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Sep 17, 2025 |
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