CVE-2025-38023
Analyzed Analyzed - Analysis Complete
BaseFortify

Publication date: 2025-06-18

Last updated on: 2025-12-17

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: nfs: handle failure of nfs_get_lock_context in unlock path When memory is insufficient, the allocation of nfs_lock_context in nfs_get_lock_context() fails and returns -ENOMEM. If we mistakenly treat an nfs4_unlockdata structure (whose l_ctx member has been set to -ENOMEM) as valid and proceed to execute rpc_run_task(), this will trigger a NULL pointer dereference in nfs4_locku_prepare. For example: BUG: kernel NULL pointer dereference, address: 000000000000000c PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP PTI CPU: 15 UID: 0 PID: 12 Comm: kworker/u64:0 Not tainted 6.15.0-rc2-dirty #60 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 Workqueue: rpciod rpc_async_schedule RIP: 0010:nfs4_locku_prepare+0x35/0xc2 Code: 89 f2 48 89 fd 48 c7 c7 68 69 ef b5 53 48 8b 8e 90 00 00 00 48 89 f3 RSP: 0018:ffffbbafc006bdb8 EFLAGS: 00010246 RAX: 000000000000004b RBX: ffff9b964fc1fa00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: fffffffffffffff4 RDI: ffff9ba53fddbf40 RBP: ffff9ba539934000 R08: 0000000000000000 R09: ffffbbafc006bc38 R10: ffffffffb6b689c8 R11: 0000000000000003 R12: ffff9ba539934030 R13: 0000000000000001 R14: 0000000004248060 R15: ffffffffb56d1c30 FS: 0000000000000000(0000) GS:ffff9ba5881f0000(0000) knlGS:00000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000000000c CR3: 000000093f244000 CR4: 00000000000006f0 Call Trace: <TASK> __rpc_execute+0xbc/0x480 rpc_async_schedule+0x2f/0x40 process_one_work+0x232/0x5d0 worker_thread+0x1da/0x3d0 ? __pfx_worker_thread+0x10/0x10 kthread+0x10d/0x240 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x34/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Modules linked in: CR2: 000000000000000c ---[ end trace 0000000000000000 ]--- Free the allocated nfs4_unlockdata when nfs_get_lock_context() fails and return NULL to terminate subsequent rpc_run_task, preventing NULL pointer dereference.
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Meta Information
Published
2025-06-18
Last Modified
2025-12-17
Generated
2026-05-06
AI Q&A
2025-06-18
EPSS Evaluated
2026-05-05
NVD
Affected Vendors & Products
Showing 14 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 4.12 (inc) to 5.4.294 (exc)
linux linux_kernel From 5.5 (inc) to 5.10.238 (exc)
linux linux_kernel From 5.11 (inc) to 5.15.184 (exc)
linux linux_kernel From 5.16 (inc) to 6.1.140 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.92 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.30 (exc)
linux linux_kernel From 6.13 (inc) to 6.14.8 (exc)
linux linux_kernel 6.15
linux linux_kernel 6.15
linux linux_kernel 6.15
linux linux_kernel 6.15
linux linux_kernel 6.15
linux linux_kernel 6.15
debian debian_linux 11.0
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.
Attack-Flow Graph
AI Powered Q&A
How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash due to a NULL pointer dereference when handling NFS lock contexts under low memory conditions. A kernel crash can lead to system instability, denial of service, and potential disruption of services relying on NFS. This could affect system availability and reliability.


Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's NFS (Network File System) implementation. When the system runs low on memory, the function nfs_get_lock_context() fails to allocate memory for nfs_lock_context and returns an error (-ENOMEM). However, if the code mistakenly treats this error as a valid lock context and proceeds to execute rpc_run_task(), it leads to a NULL pointer dereference in the function nfs4_locku_prepare. This causes a kernel crash (BUG) due to accessing invalid memory. The fix involves properly freeing the allocated nfs4_unlockdata when nfs_get_lock_context() fails and returning NULL to stop further processing, thus preventing the NULL pointer dereference.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring the system kernel logs for NULL pointer dereference errors related to NFS, specifically messages mentioning 'nfs4_locku_prepare' and 'BUG: kernel NULL pointer dereference'. You can use commands like 'dmesg | grep -i nfs4_locku_prepare' or 'journalctl -k | grep -i nfs' to look for such kernel oops or crash messages indicating the issue.


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation involves updating the Linux kernel to a version where this vulnerability is fixed, as the issue is resolved by properly handling the failure of nfs_get_lock_context and preventing NULL pointer dereference. Until an update is applied, consider limiting or disabling NFS usage if feasible to reduce exposure.


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