High severity · published Sep 11, 2026
CVE-2026-89684
nfsd: fix cpntf publish race in nfs4_init_cp_state
7.5
CVSS
0.5%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix cpntf publish race in nfs4_init_cp_state nfs4_alloc_init_cpntf_state() published the new cpntf entry into the s2s_cp_stateids IDR (with cs_type set) in one s2s_cp_lock section, then took the lock again to list_add() it onto p_stid->sc_cp_list. In the gap the entry is reachable by so_id but cp_list is still {NULL,NULL} from kzalloc. A racing OFFLOAD_CANCEL (so_id is echoed to the client as cnr_stateid, so any NFSv4.2 client can drive it) reaches manage_cpntf_state() -> _free_cpntf_state_locked() and does list_del() on the zeroed list_head, oopsing the server. Fold the cs_type assignment and the list_add() into the same critical section as idr_alloc_cyclic(), so a concurrent lookup either misses the entry or sees a fully linked cp_list. INIT_LIST_HEAD() the entry after allocation and switch _free_cpntf_state_locked() to list_del_init() so a stale unlink is a no-op. nfs4_init_copy_state() passes NULL p_stid and skips the list_add, preserving NFS4_COPY_STID semantics.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
624322f1adc58acd0b69f77a6ddc764207e97241 before 63e18fc65587fd3f7b4c6d70e96d32fc41d82ba3; 624322f1adc58acd0b69f77a6ddc764207e97241 before 6ac469a274e3c7d87fc46ba46d83b95009680407; 624322f1adc58acd0b69f77a6ddc764207e97241 before 8eeca993357a0bc35aaefebfd7462ac7b0a21d9a; 624322f1adc58acd0b69f77a6ddc764207e97241 before bfeac42d9074e539bacd1898dd8c14b7f5776620; 624322f1adc58acd0b69f77a6ddc764207e97241 before 21d6c5957f5ca97d7352e60f55ea412beb9419f5; 624322f1adc58acd0b69f77a6ddc764207e97241 before a631a26a8777bb235eabd478bbbaf26a4db750bf; +3 more · source: vendor