CVE-2023-53360: NFSv4.2: Rework scratch handling for READ_PLUS (again)

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-09-17 · updated 2026-08-04
Weakness: CWE-415

Description

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.

Affected products

Linux kernel: from 6.4 before 6.4.16; from 6.5 before 6.5.3 — fixed in 6.4.16, 6.5.3

How to fix

Upgrade to a fixed version: Linux kernel 6.4.16, 6.5.3. Check the vendor advisory for mitigations.

References

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