CVE-2024-35882: SUNRPC: Fix a slow server-side memory leak with RPC-over-TCP

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-19 · updated 2026-08-04
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: SUNRPC: Fix a slow server-side memory leak with RPC-over-TCP Jan Schunk reports that his small NFS servers suffer from memory exhaustion after just a few days. A bisect shows that commit e18e157bb5c8 ("SUNRPC: Send RPC message on TCP with a single sock_sendmsg() call") is the first bad commit. That commit assumed that sock_sendmsg() releases all the pages in the underlying bio_vec array, but the reality is that it doesn't. svc_xprt_release() releases the rqst's response pages, but the record marker page fragment isn't one of those, so it is never released. This is a narrow fix that can be applied to stable kernels. A more extensive fix is in the works.

Affected products

Linux kernel: from 6.6 before 6.6.26; from 6.7 before 6.8.5; 6.9-rc1, 6.9-rc2 — fixed in 6.6.26, 6.8.5

How to fix

Upgrade to a fixed version: Linux kernel 6.6.26, 6.8.5. Check the vendor advisory for mitigations.

References

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