CVE-2026-98920
Received
Received - Intake
Memory Allocation Tagging Flaw in Linux Kernel
Vulnerability report for CVE-2026-98920, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-23
Last updated on: 2026-10-23
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix missing alloc tagging of direct mempool allocations
Commit 1d78d56c43ef ("netfs: Fix folio_queue ENOMEM in writeback by
adding a mempool") added a mempool for the folio_queues and made the
request, subrequest and folio_queue allocations distinguish between
writeback and everything else. Writeback is part of memory reclaim
and must not fail due to ENOMEM, so it allocates under GFP_NOFS
through mempool_alloc(), which may dip into the pool's reserve and,
if that runs empty, wait for elements to be returned. The
GFP_KERNEL paths, which can return -ENOMEM to their callers, invoke
the pool's ->alloc() callback directly instead.
The direct call, however, skips the alloc_hooks() wrapper that the
mempool_alloc() macro provides. The pool callbacks, mempool_alloc_slab()
and mempool_kmalloc(), call kmem_cache_alloc_noprof() and kmalloc_noprof()
and rely on current->alloc_tag having been set by the caller. With
CONFIG_MEM_ALLOC_PROFILING_DEBUG=y this leads to
current->alloc_tag not set
WARNING: ./include/linux/alloc_tag.h:161 at __alloc_tagging_slab_alloc_hook
alloc_tag was not set
WARNING: ./include/linux/alloc_tag.h:166 at __alloc_tagging_slab_free_hook
at allocation and free time respectively, as reported when reading
files on a CIFS mount. The allocations are also missing from
/proc/allocinfo.
Wrap the direct ->alloc() invocations in alloc_hooks() with a new
mempool_alloc_noreserve() helper in include/linux/mempool.h, next to
the other alloc_hooks()-wrapped macros such as mempool_alloc(). The
GFP_KERNEL paths keep their failable allocation semantics, they just
get tagged now.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| Linux | Linux | 15ed8a9b7c63e9171f5139a6aaa1ffb61809861f |
| Linux | Linux | 1d78d56c43ef3768183e8370e7367b162700e049 |
| Linux | Linux | 1d78d56c43ef3768183e8370e7367b162700e049 |
| Linux | Linux | b343252d6f536203dd0660f676190dcbf6d2ecdc |
| Linux | Linux | 3f6d7f8a5416d852648d15a05e895f1195ee8a85 |
| Linux | Linux | 6.12.114 |
| Linux | Linux | 7.1.8 |
| Linux | Linux | 7.2 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
