CVE-2026-98920
UnknownSummary
In the Linux kernel, a bug was fixed in the netfs subsystem where direct mempool allocation calls bypassed the alloc_hooks() wrapper, causing warnings about current->alloc_tag not being set during allocation and free when CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled. The issue occurred e.g. when reading files on a CIFS mount, and allocations were missing from /proc/allocinfo.
Risk Assessment
The bug produces spurious kernel warnings and missing allocation statistics, which hampers diagnostics and may mask real memory issues. It does not directly lead to privilege escalation or data loss, but reduces system stability and monitoring quality.
Recommendation
Update the Linux kernel to a version containing the fix (the commit introducing mempool_alloc_noreserve()). If CONFIG_MEM_ALLOC_PROFILING_DEBUG is not enabled, the risk is limited, but the update should still be scheduled in the standard cycle.
Other vulnerabilities in Linux kernel
See all- CVE-2026-58942High
In do_fault_around of memory.c, there is a possible use after free due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed.
- CVE-2026-58847Unknown
In kvm_vfio_pviommu_attach of vfio.c, there is a possible double free due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
- CVE-2026-58829High
In fuse_backing_mmap of backing.c, there is a possible memory corruption due to a use after free. This could lead to local escalation of privilege with no additional execution privileges needed.
- CVE-2026-58828High
In multiple functions of base.c, there is a possible use-after-free due to a race condition. This could lead to local escalation of privilege with no additional execution privileges needed.
- CVE-2026-58827High
In multiple functions of dma-buf.c, there is a possible use after free due to a race condition. This could lead to local escalation of privilege with no additional execution privileges needed.
- CVE-2026-58826High
In ksys_unshare of fork.c, there is a possible memory corruption due to a use after free. This could lead to local escalation of privilege with no additional execution privileges needed.
- CVE-2026-58825High
In multiple functions of fork.c, there is a possible use after free due to a logic error in the code. This could lead to local escalation of privilege with no additional execution privileges needed.
- CVE-2026-99242Unknown
In the Linux kernel, a race between fallocate and mmap reads in NTFS was fixed. Fallocate only took invalidate_lock for punch hole, collapse range and insert range operations, and during standard allocation new clusters were mapped before being zeroed, allowing concurrent mmap page faults to read uninitialized disk data.
- CVE-2026-99241Unknown
In the Linux kernel, a missing lock in ntfs_filemap_page_mkwrite() was fixed; it called iomap_page_mkwrite() without holding mapping->invalidate_lock. A concurrent truncate or fallocate could be invalidating pagecache and rewriting the runlist while the write fault mapped blocks and dirtied the folio.
- CVE-2026-99240Unknown
In the Linux kernel, the DAMON subsystem (mm/damon/core) has a division-by-zero bug when a DAMOS quota goal has a target_value of zero. The fix moves handling of this corner case to the core layer by adding validation in damos_commit_quota_goal(), which now returns an error for zero target values.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS