Common Weakness Enumeration

CWE-553

Weakness Allowed

Command Shell in Externally Accessible Directory

Abstraction: Variant · Status: Incomplete

A possible shell file exists in /cgi-bin/ or other accessible directories. This is extremely dangerous and can be used by an attacker to execute commands on the web server.

Mapping guidance

This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.

Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Relationships and members

ChildOf: CWE-552 · View CWE-1000

Modes of introduction

Implementation

Operation

Content history

Submission: Anonymous Tool Vendor (under NDA) · 2006-07-19 · CWE Draft 3

Modification: Eric Dalci · Cigital · 2008-07-01 · CWE 1.0

updated Potential_Mitigations, Time_of_Introduction

Modification: CWE Content Team · MITRE · 2008-09-08 · CWE 1.0

updated Relationships, Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2011-06-01 · CWE 1.13

updated Common_Consequences

Modification: CWE Content Team · MITRE · 2012-05-11 · CWE 2.2

updated Relationships

Modification: CWE Content Team · MITRE · 2012-10-30 · CWE 2.3

updated Potential_Mitigations

Modification: CWE Content Team · MITRE · 2014-07-30 · CWE 2.8

updated Relationships

Modification: CWE Content Team · MITRE · 2017-11-08 · CWE 3.0

updated Taxonomy_Mappings

Modification: CWE Content Team · MITRE · 2019-01-03 · CWE 3.2

updated Related_Attack_Patterns

Modification: CWE Content Team · MITRE · 2020-02-24 · CWE 4.0

updated Relationships

Modification: CWE Content Team · MITRE · 2023-04-27 · CWE 4.11

updated Relationships

Modification: CWE Content Team · MITRE · 2023-06-29 · CWE 4.12

updated Mapping_Notes

Modification: CWE Content Team · MITRE · 2025-12-11 · CWE 4.19

updated Applicable_Platforms, Weakness_Ordinalities

2 vulnerabilities reference this CWE, most recent first.

CVE-2025-66620 (GCVE-0-2025-66620)

Vulnerability from cvelistv5 – Published: 2026-01-07 20:08 – Updated: 2026-01-07 20:16

Title

Columbia Weather Systems MicroServer Command Shell in Externally Accessible Directory

Summary

An unused webshell in MicroServer allows unlimited login attempts, with sudo rights on certain files and directories. An attacker with admin access to MicroServer can gain limited shell access, enabling persistence through reverse shells, and the ability to modify or remove data stored in the file system.

Severity

8.6 (High)


                        
                          CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-01-07 20:15 UTC

CWE

CWE-553 - Command Shell in Externally Accessible Directory

Assigner

icscert CNA under the icscert root

CNA scorecard B 75/100 over 343 records in the last 180 days details

References

2 references

URL	Tags
https://www.cisa.gov/news-events/ics-advisories/i…
https://github.com/cisagov/CSAF/blob/develop/csaf…

Impacted products

1 product

Vendor	Product	Version
Columbia Weather Systems	MicroServer	Affected: 0 , < MS_4.1_14142 (custom)

Date Public

2026-01-06 18:00

Credits

UsrPacific/Columbia Weather Systems reported these vulnerabilities to CISA.

Show details on NVD website

JSON

To clipboard

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GHSA-MH3M-M8M5-X43F

Vulnerability from github – Published: 2026-01-07 21:31 – Updated: 2026-01-07 21:31

Details

Severity

8.0 (High)


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

8.6 (High)


                  
                    CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2025-66620"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-553"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-01-07T21:15:59Z",
    "severity": "HIGH"
  },
  "details": "An unused webshell in MicroServer allows unlimited login attempts, with sudo rights on certain files and directories. An attacker with admin access to MicroServer can gain limited shell access, enabling persistence through reverse shells, and the ability to modify or remove data stored in the file system.",
  "id": "GHSA-mh3m-m8m5-x43f",
  "modified": "2026-01-07T21:31:56Z",
  "published": "2026-01-07T21:31:56Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66620"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-006-01.json"
    },
    {
      "type": "WEB",
      "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-26-006-01"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
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      "score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

Mitigation

Installation System Configuration

Remove any Shells accessible under the web root folder and children directories.

CAPEC-650: Upload a Web Shell to a Web Server

By exploiting insufficient permissions, it is possible to upload a web shell to a web server in such a way that it can be executed remotely. This shell can have various capabilities, thereby acting as a "gateway" to the underlying web server. The shell might execute at the higher permission level of the web server, providing the ability the execute malicious code at elevated levels.

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