SEPTEMBER 13, 2026
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Case File

CVE-2026-89676

CRITICAL · CVSS 9.8 EPSS 0.45%

Source: NVD + CISA KEV + EPSS · Published 2026-09-11 · Last synced 2026-09-13

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's NFS server (nfsd) specifically during asynchronous COPY operations, where improper handling of state IDs can lead to dereferencing reused memory. This flaw may allow an attacker to exploit stale memory references, potentially leading to memory corruption or denial of service. Organizations running Linux systems that utilize NFS should prioritize patching this vulnerability to mitigate risks associated with memory management issues.

CVE
CVE-2026-89676
Severity
CRITICAL
CVSS
9.8
EPSS
0.45%
Linux

Original NVD Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix stale s2s_cp_stateids IDR entry for async COPY For an async COPY, nfsd4_copy() called nfs4_init_copy_state() before dup_copy_fields(), so the s2s_cp_stateids IDR was pointed at &u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is reused by the next request. dup_copy_fields() copies only the value into async_copy, so the IDR slot dangled at the transient buffer for the whole background copy. Any IDR walker then dereferences reused request memory: the laundromat reads cs_type from it and, if the bytes look like an expired NFS4_COPYNOTIFY_STID, follows into refcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has the same exposure via idr_find(). Duplicate the fields first, then register the stateid on the stable async_copy. result->cb_stateid is unchanged.