CVE-2026-43492

Kernel hang via unchecked zero-count subtraction

Published May 19, 2026 · Updated May 19, 2026

Integer underflow in the Linux Kernel MPI helper allows local users to hang the kernel through a crafted KEYCTL_PKEY_ENCRYPT request. In mpi_read_raw_from_sgl(), an oversized all-zero scatterlist lets the leading-zero count exceed nbytes before unsigned subtraction wraps. A local user can set out_len above in_len with zero-filled input, causing the kernel to spin indefinitely and emit soft-lockup reports.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in the Linux Kernel MPI helper allows local users to hang the kernel through a crafted KEYCTL_PKEY_ENCRYPT request. In mpi_read_raw_from_sgl(), an oversized all-zero scatterlist lets the leading-zero count exceed nbytes before unsigned subtraction wraps. A local user can set out_len above in_len with zero-filled input, causing the kernel to spin indefinitely and emit soft-lockup reports.

The record

CVE
CVE-2026-43492
Published
May 19, 2026
Updated
May 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-190, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 19, 2026CVE publishedPublication date reported by the CVE source.
  2. May 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2d4d1eea540b27c72488fd1914674c42473d53df <26d3a97ad46c7a9226ec04d4bf35bd4998a97d16
  2. Affected versionversion=2d4d1eea540b27c72488fd1914674c42473d53df <2aa77a18dc7f2670497fe3ee5acbeda0b57659e5
  3. Affected versionversion=2d4d1eea540b27c72488fd1914674c42473d53df <30e513e755bb381afce6fb57cdc8694136193f22
  4. Affected versionversion=2d4d1eea540b27c72488fd1914674c42473d53df <8637dfb4c1d8a7026ef681f2477c6de8b71c4003
  5. Affected versionversion=2d4d1eea540b27c72488fd1914674c42473d53df <8c2f1288250a90a4b5cabed5d888d7e3aeed4035
  6. Affected versionversion=4.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2d4d1eea540b27c72488fd1914674c42473d53df <26d3a97ad46c7a9226ec04d4bf35bd4998a97d16; version=2d4d1eea540b27c72488fd1914674c42473d53df <2aa77a18dc7f2670497fe3ee5acbeda0b57659e5; version=2d4d1eea540b27c72488fd1914674c42473d53df <30e513e755bb381afce6fb57cdc8694136193f22; version=2d4d1eea540b27c72488fd1914674c42473d53df <8637dfb4c1d8a7026ef681f2477c6de8b71c4003; version=2d4d1eea540b27c72488fd1914674c42473d53df <8c2f1288250a90a4b5cabed5d888d7e3aeed4035; version=4.4

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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