CVE-2022-50410: NFSD: Protect against send buffer overflow in NFSv2 READ

Severity: high (CVSS 7.8 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: 2025-09-18 · updated 2026-08-04
Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Protect against send buffer overflow in NFSv2 READ Since before the git era, NFSD has conserved the number of pages held by each nfsd thread by combining the RPC receive and send buffers into a single array of pages. This works because there are no cases where an operation needs a large RPC Call message and a large RPC Reply at the same time. Once an RPC Call has been received, svc_process() updates svc_rqst::rq_res to describe the part of rq_pages that can be used for constructing the Reply. This means that the send buffer (rq_res) shrinks when the received RPC record containing the RPC Call is large. A client can force this shrinkage on TCP by sending a correctly- formed RPC Call header contained in an RPC record that is excessively large. The full maximum payload size cannot be constructed in that case.

Affected products

Linux kernel: before 5.10.220; from 5.11 before 5.15.75; from 5.16 before 5.19.17; from 6.0 before 6.0.3 — fixed in 5.10.220, 5.15.75, 5.19.17, 6.0.3

How to fix

Upgrade to a fixed version: Linux kernel 5.10.220, 5.15.75, 5.19.17, 6.0.3. Check the vendor advisory for mitigations.

References

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