---
name: "spectre-meltdown-checker"
section: "1"
platform: "linux"
package: "spectre-meltdown-checker"
version: "0.46-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/spectre-meltdown-checker"
---

# spectre-meltdown-checker(1)

Spectre & Meltdown vulnerability/mitigation checker

## NAME

Spectre - Spectre & Meltdown vulnerability/mitigation checker

## DESCRIPTION

Spectre and Meltdown mitigation detection tool v0.46

-

  Usage:

- Live mode (auto):

  spectre-meltdown-checker \[options\]

-

  Live mode (manual): spectre-meltdown-checker \[options\] \<\[--kernel \<kimage\>\] \[--config \<kconfig\>\] \[--map \<mapfile\>\]\> **--live** Offline mode:       spectre-meltdown-checker \[options\] \<\[--kernel \<kimage\>\] \[--config \<kconfig\>\] \[--map \<mapfile\>\]\>

-

  Modes:

-

  Two modes are available.

-

  First mode is the "live" mode (default), it does its best to find information about the currently running kernel. To run under this mode, just start the script without any option (you can also use **--live** explicitly)

-

  Second mode is the "offline" mode, where you can inspect a non-running kernel. This mode is automatically enabled when you specify the location of the kernel file, config and System.map files:

- **--kernel** kernel\_file

  specify a (possibly compressed) Linux or BSD kernel file

- **--config** kernel\_config

  specify a kernel config file (Linux only)

- **--map** kernel\_map\_file

  specify a kernel System.map file (Linux only)

-

  If you want to use live mode while specifying the location of the kernel, config or map file yourself, you can add **--live** to the above options, to tell the script to run in live mode instead of the offline mode, which is enabled by default when at least one file is specified on the command line.

-

  Options:

- **--no-color**

  don't use color codes

- **--verbose**, **-v**

  increase verbosity level, possibly several times

- **--explain**

  produce an additional human-readable explanation of actions to take to mitigate a vulnerability

- **--paranoid**

  require IBPB to deem Variant 2 as mitigated also require SMT disabled + unconditional L1D flush to deem Foreshadow-NG VMM as mitigated also require SMT disabled to deem MDS vulnerabilities mitigated

- **--no-sysfs**

  don't use the */sys* interface even if present \[Linux\]

- **--sysfs-only**

  only use the */sys* interface, don't run our own checks \[Linux\]

- **--coreos**

  special mode for CoreOS (use an ephemeral toolbox to inspect kernel) \[Linux\]

- **--arch-prefix** PREFIX

  specify a prefix for cross-inspecting a kernel of a different arch, for example "aarch64-linux-gnu-", so that invoked tools will be prefixed with this (i.e. aarch64-linux-gnu-objdump)

- **--batch** text

  produce machine readable output, this is the default if **--batch** is specified alone

- **--batch** short

  produce only one line with the vulnerabilities separated by spaces

- **--batch** json

  produce JSON output formatted for Puppet, Ansible, Chef...

- **--batch** nrpe

  produce machine readable output formatted for NRPE

- **--batch** prometheus

  produce output for consumption by prometheus-node-exporter

- **--variant** VARIANT

  specify which variant you'd like to check, by default all variants are checked. can be used multiple times (e.g. **--variant** 3a **--variant** l1tf) for a list of supported VARIANT parameters, use **--variant** help

- **--cve** CVE

  specify which CVE you'd like to check, by default all supported CVEs are checked can be used multiple times (e.g. **--cve** CVE-2017-5753 **--cve** CVE-2020-0543)

- **--hw-only**

  only check for CPU information, don't check for any variant

- **--no-hw**

  skip CPU information and checks, if you're inspecting a kernel not to be run on this host

- **--vmm** \[auto,yes,no\]

  override the detection of the presence of a hypervisor, default: auto

- **--allow-msr-write**

  allow probing for write-only MSRs, this might produce kernel logs or be blocked by your system

- **--cpu** \[#,all\]

  interact with CPUID and MSR of CPU core number #, or all (default: CPU core 0)

- **--update-fwdb**

  update our local copy of the CPU microcodes versions database (using the awesome MCExtractor project and the Intel firmwares GitHub repository)

- **--update-builtin-fwdb**

  same as **--update-fwdb** but update builtin DB inside the script itself

- **--dump-mock-data**

  used to mimick a CPU on an other system, mainly used to help debugging this script

-

  Return codes:

-

  0 (not vulnerable), 2 (vulnerable), 3 (unknown), 255 (error)

-

  IMPORTANT: A false sense of security is worse than no security at all. Please use the **--disclaimer** option to understand exactly what this script does.

## SEE ALSO

The full documentation for **Spectre** is maintained as a Texinfo manual.  If the **info** and **Spectre** programs are properly installed at your site, the command

-

  **info Spectre**

should give you access to the complete manual.