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Linux KernelOperating system · Linux

CVE-2026-46294

HIGH · 7.8 CVSS v3.1 Published 2026-06-08
Fix available
A fix is available. Upgrade to 5.10.258 / 5.15.209 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: dm: fix a buffer overflow in ioctl processing Tony Asleson (using Claude) found a buffer overflow in dm-ioctl in the function retrieve_status: 1. The code in retrieve_status checks that the output string fits into the output buffer and writes the output string there 2. Then, the code aligns the "outptr" variable to the next 8-byte boundary: outptr = align_ptr(outptr); 3. The alignment doesn't check overflow, so outptr could point past the buffer end 4. The "for" loop is iterated again, it executes: remaining = len - (outptr - outbuf); 5. If "outptr" points past "outbuf + len", the arithmetics wraps around and the variable "remaining" contains unusually high number 6. With "remaining" being high, the code writes more data past the end of the buffer Luckily, this bug has no security implications because: 1. Only root can issue device mapper ioctls 2. The commonly used libraries that communicate with device mapper (libdevmapper and devicemapper-rs) use buffer size that is aligned to 8 bytes - thus, "outptr = align_ptr(outptr)" can't overshoot the input buffer and the bug can't happen accidentally

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 Linux kernel's device mapper ioctl processing in retrieve_status function - the align_ptr() call can advance the output pointer past buffer end without overflow checking, causing subsequent writes to extend beyond allocated buffer boundaries.

MitigationApply kernel patch or update to patched kernel version; while exploitability is limited (root-only, aligned library buffers), patching is recommended for defense in depth.

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:>= 2.6.12.1, < 5.10.258>= 5.11, < 5.15.209>= 5.16, < 6.1.175>= 6.2, < 6.6.140>= 6.7, < 6.12.88>= 6.13, < 6.18.30>= 6.19, < 7.0.7= 2.6.12

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. Identify kernel version
    Run `uname -r` or read `/proc/version` to get the running kernel version
    Affected if The kernel version falls within the affected ranges: >= 2.6.12.1 and < 5.10.258, or >= 5.11 and < 5.15.209, or >= 5.16 and < 6.1.175, or >= 6.2 and < 6.6.140, or >= 6.7 and < 6.12.88, or >= 6.13 and < 6.18.30, or >= 6.19 and < 7.0.7, or exactly 2.6.12
  2. Verify device mapper is in use
    Check for active device mapper devices by listing `/sys/class/block/` for dm-* entries, or run `dmsetup status` or `dmsetup ls`
    Affected if Device mapper devices (dm-0, dm-1, etc.) exist or dmsetup returns any active mappings
  3. Confirm device mapper ioctl access
    Check permissions on `/dev/mapper/control` (or `/dev/device-mapper`) using `ls -la /dev/mapper/control` or identify if unprivileged user namespaces are enabled (check `cat /proc/sys/kernel/unprivileged_userns_clone`)
    Affected if The device mapper control device is world-accessible or unprivileged user namespaces are enabled, allowing untrusted users to trigger ioctl calls
  4. Check for exposed DM targets to untrusted users
    Identify if any device mapper targets (like dm-linear, dm-stripe, dm-crypt) are accessible to untrusted users via block device permissions in `/sys/class/block/dm-*/device` or if containerized workloads have direct access to device mapper
    Affected if Untrusted users or containers have direct access to dm devices without proper isolation

A system is affected if it runs an affected kernel version AND has active device mapper devices with accessible ioctl interfaces to untrusted users, enabling the buffer overflow to be triggered.

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 5.10.258 / 5.15.209 / 6.1.175 or later
Fixed in 5.10.2585.15.2096.1.175
Vendor patch git.kernel.org →
Interim mitigation

Apply kernel patch or update to patched kernel version; while exploitability is limited (root-only, aligned library buffers), patching is recommended for defense in depth.

Recommended fix High confidence

5.10.258, 5.15.209, 6.1.175, or 6.6.140 (depending on which branch you are on)

  1. Identify the current running kernel version using 'uname -r' or 'cat /proc/version'
  2. Determine which version branch the current kernel belongs to (e.g., 5.10.x, 5.15.x, 6.1.x, or 6.6.x)
  3. Upgrade the kernel to the first fixed version in the affected branch: for 5.10.x line upgrade to 5.10.258 or later; for 5.11-5.15.x upgrade to 5.15.209 or later; for 5.16-6.1.x upgrade to 6.1.175 or later; for 6.2-6.6.x upgrade to 6.6.140 or later
  4. Reboot the system to load the fixed kernel
  5. Verify the kernel version post-reboot with 'uname -r' to confirm the fix is applied
Caveat Kernel upgrades may require updates to out-of-tree kernel modules or driver compatibility; ensure dependent modules are rebuilt for the new kernel version

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing4.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,540
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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-2026-46294 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
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  • Version or environment caveats, and links to real fixes
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