Use After Free Affecting gfs2-kmp-default package, versions <6.12.0-160000.36.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.12% (2nd percentile)

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  • Snyk IDSNYK-SLES1600-GFS2KMPDEFAULT-18348181
  • published28 Jul 2026
  • disclosed21 Jul 2026

Introduced: 21 Jul 2026

NewCVE-2026-45837  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 gfs2-kmp-default to version 6.12.0-160000.36.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream gfs2-kmp-default package and not the gfs2-kmp-default package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix use-after-free in arena_vm_close on fork

arena_vm_open() only bumps vml->mmap_count but never registers the child VMA in arena->vma_list. The vml->vma always points at the parent VMA, so after parent munmap the pointer dangles. If the child then calls bpf_arena_free_pages(), zap_pages() reads the stale vml->vma triggering use-after-free.

Fix this by preventing the arena VMA from being inherited across fork with VM_DONTCOPY, and preventing VMA splits via the may_split callback.

Also reject mremap with a .mremap callback returning -EINVAL. A same-size mremap(MREMAP_FIXED) on the full arena VMA reaches copy_vma() through the following path:

check_prep_vma() - returns 0 early: new_len == old_len skips VM_DONTEXPAND check prep_move_vma() - vm_start == old_addr and vm_end == old_addr + old_len so may_split is never called move_vma() copy_vma_and_data() copy_vma() vm_area_dup() - copies vm_private_data (vml pointer) vm_ops->open() - bumps vml->mmap_count vm_ops->mremap() - returns -EINVAL, rollback unmaps new VMA

The refcount ensures the rollback's arena_vm_close does not free the vml shared with the original VMA.

CVSS Base Scores

version 3.1