CVE-2026-45993

Local system interruption via speculative syscall indexing

Published May 27, 2026 · Updated May 27, 2026

Speculative bounds-check bypass in the Linux Kernel allows local users to interrupt affected LoongArch systems via system calls. In arch/loongarch/kernel/syscall.c, do_syscall uses a userspace-controlled syscall number to index sys_call_table after a bounds check without constraining speculative execution. Exploitation requires local code on an affected LoongArch build; the public record does not state whether interruption manifests as a hang, crash, or reboot.

CVSS severity5.5
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Speculative bounds-check bypass in the Linux Kernel allows local users to interrupt affected LoongArch systems via system calls. In arch/loongarch/kernel/syscall.c, do_syscall uses a userspace-controlled syscall number to index sys_call_table after a bounds check without constraining speculative execution. Exploitation requires local code on an affected LoongArch build; the public record does not state whether interruption manifests as a hang, crash, or reboot.

The record

CVE
CVE-2026-45993
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <6.12.86
  2. Affected versionversion=0 <6.18.27
  3. Affected versionversion=0 <6.6.140
  4. Affected versionversion=0 <7.0.4
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <07040904ad217545be096d4280ed33c02f6a3750
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0c965d2784fbbd7f8e3b96d875c9cfdf7c00da3d
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <108f2cd13577a410c0ad6ea00708596d9d0dfc90
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <85cbf7fb568af5358aae61925c4e66b8f5e1439d
  9. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bc84a109c2082dd0c4b38e8d923c046b41977533

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=0 <6.12.86; version=0 <6.18.27; version=0 <6.6.140; version=0 <7.0.4; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <07040904ad217545be096d4280ed33c02f6a3750; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0c965d2784fbbd7f8e3b96d875c9cfdf7c00da3d; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <108f2cd13577a410c0ad6ea00708596d9d0dfc90; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <85cbf7fb568af5358aae61925c4e66b8f5e1439d; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bc84a109c2082dd0c4b38e8d923c046b41977533

Published CVSS scores

5.5NVDCVSS: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

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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