CVE-2022-50241
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-15

Last updated on: 2025-11-25

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: NFSD: fix use-after-free on source server when doing inter-server copy Use-after-free occurred when the laundromat tried to free expired cpntf_state entry on the s2s_cp_stateids list after inter-server copy completed. The sc_cp_list that the expired copy state was inserted on was already freed. When COPY completes, the Linux client normally sends LOCKU(lock_state x), FREE_STATEID(lock_state x) and CLOSE(open_state y) to the source server. The nfs4_put_stid call from nfsd4_free_stateid cleans up the copy state from the s2s_cp_stateids list before freeing the lock state's stid. However, sometimes the CLOSE was sent before the FREE_STATEID request. When this happens, the nfsd4_close_open_stateid call from nfsd4_close frees all lock states on its st_locks list without cleaning up the copy state on the sc_cp_list list. When the time the FREE_STATEID arrives the server returns BAD_STATEID since the lock state was freed. This causes the use-after-free error to occur when the laundromat tries to free the expired cpntf_state. This patch adds a call to nfs4_free_cpntf_statelist in nfsd4_close_open_stateid to clean up the copy state before calling free_ol_stateid_reaplist to free the lock state's stid on the reaplist.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2025-09-15
Last Modified
2025-11-25
Generated
2026-05-27
AI Q&A
2025-09-15
EPSS Evaluated
2026-05-25
NVD
CVE-2022-50241
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
linux linux_kernel From 5.15.160 (inc) to 5.16 (inc)
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a use-after-free bug in the Linux kernel's NFS server (NFSD) related to inter-server copy operations. It occurs when the server tries to free an expired copy state entry that has already been freed due to the order in which LOCKU, FREE_STATEID, and CLOSE requests are processed. Specifically, if the CLOSE request is processed before the FREE_STATEID, the server frees lock states without cleaning up the copy state, leading to a use-after-free when the expired copy state is later freed.


How can this vulnerability impact me? :

This vulnerability can cause the Linux NFS server to access memory that has already been freed, potentially leading to server crashes, denial of service, or unpredictable behavior during inter-server copy operations.


Ask Our AI Assistant
Need more information? Ask your question to get an AI reply (Powered by our expertise)
0/70
EPSS Chart