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Linux KernelOperating system · Linux

CVE-2026-46281

HIGH · 7.8 CVSS v3.1 Published 2026-06-08
Fix available
A fix is available. Upgrade to 6.18.27 / 7.0.4 or later.
See remediation →
80/100
Remediation priority · High
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: vmalloc: fix buffer overflow in vrealloc_node_align() Commit 4c5d3365882d ("mm/vmalloc: allow to set node and align in vrealloc") added the ability to force a new allocation if the current pointer is on the wrong NUMA node, or if an alignment constraint is not met, even if the user is shrinking the allocation. On this path (need_realloc), the code allocates a new object of 'size' bytes and then memcpy()s 'old_size' bytes into it. If the request is to shrink the object (size < old_size), this results in an out-of-bounds write on the new buffer. Fix this by bounding the copy length by the new allocation size.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Buffer overflow in vrealloc_node_align() where the code allocates a new buffer of 'size' bytes but copies 'old_size' bytes via memcpy(). When shrinking an allocation (size < old_size), this results in an out-of-bounds write beyond the new buffer's bounds.

MitigationFix by bounding the memcpy length to min(size, old_size); requires patching the Linux kernel, recompiling, and deploying the updated kernel.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.18, < 6.18.27>= 6.19, < 7.0.4= 7.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check the running kernel version
    Run `uname -r` or `cat /proc/version` to obtain the kernel version
    Affected if The version falls within 6.18 to 6.18.26, 6.19 to 7.0.3, or equals 7.1
  2. Determine if NUMA support is enabled
    Check if `/proc/buddyinfo` shows multiple NUMA nodes, or run `numactl --hardware`
    Affected if The system has multiple NUMA nodes and the kernel version is vulnerable
  3. Verify the kernel build configuration for SLAB allocator
    Check if `CONFIG_SLUB` or `CONFIG_SLAB` is enabled in `/boot/config-$(uname -r)` or via `cat /proc/config.gz` if available
    Affected if The SLUB/SLAB allocator is enabled and the kernel version is vulnerable
  4. Confirm the presence of vrealloc_node_align symbol
    Check if the function exists in the kernel via `grep vrealloc_node_align /boot/System.map-$(uname -r)` or `cat /proc/kallsyms`
    Affected if The function is present and the kernel version is vulnerable

A system is affected if it runs a Linux kernel version within the affected ranges (6.18.x before 6.18.27, 6.19.x before 7.0.4, or 7.1) and uses the SLAB/SLUB allocator with NUMA or alignment-dependent memory reallocation operations.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.18.27 / 7.0.4 or later
Fixed in 6.18.277.0.4
Vendor patch git.kernel.org →
Interim mitigation

Fix by bounding the memcpy length to min(size, old_size); requires patching the Linux kernel, recompiling, and deploying the updated kernel.

Recommended fix High confidence

6.18.27+ for 6.18.x kernels; 7.0.4+ for 6.19.x kernels; next stable release beyond 7.1.x for 7.1.x kernels

  1. 1. Identify the currently running kernel version using 'uname -r' or 'cat /proc/version'
  2. 2. Check if the running kernel version is within any of the affected ranges: >= 6.18 and < 6.18.27, >= 6.19 and < 7.0.4, or 7.1
  3. 3. For systems running 6.18.x: upgrade to kernel version 6.18.27 or later
  4. 4. For systems running 6.19.x: upgrade to kernel version 7.0.4 or later
  5. 5. For systems running 7.1.x: upgrade to the next stable release beyond 7.1 (such as 7.1.1 or later when available)
  6. 6. After kernel upgrade, reboot the system to apply the patched kernel
  7. 7. Verify the fix is applied by checking the kernel version and confirming the commit 82d1f01292d3f09bf063f829f8ab8de12b4280a1 is included in the new kernel
Caveat Kernel upgrades may require driver rebuilding or system reboots; ensure compatibility with local system configuration before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-46281 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data