Vulnerability-Lookup

GHSA-QMW3-745M-W99G

Vulnerability from github – Published: 2026-10-07 18:03 – Updated: 2026-10-07 18:03

Summary

Backstage: Improper validation of TechDocs MkDocs configuration

Details

Impact

An attacker who can provide configuration to a TechDocs build may execute code in the generator runtime. Impact is greatest when documentation generation runs with backend credentials or host access.

Patches

Patched in @backstage/plugin-techdocs-node version 1.15.4.

Workarounds

Use external TechDocs generation in an isolated environment without sensitive credentials or host access. Restrict and review changes to documentation configuration before generation.

Severity

8.8 (High)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@backstage/plugin-techdocs-node"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.15.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-106558"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-502"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-07T18:03:12Z",
    "nvd_published_at": "2026-10-07T15:17:15Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nAn attacker who can provide configuration to a TechDocs build may execute code in the generator runtime. Impact is greatest when documentation generation runs with backend credentials or host access.\n\n### Patches\n\nPatched in `@backstage/plugin-techdocs-node` version `1.15.4`.\n\n### Workarounds\n\nUse external TechDocs generation in an isolated environment without sensitive credentials or host access. Restrict and review changes to documentation configuration before generation.",
  "id": "GHSA-qmw3-745m-w99g",
  "modified": "2026-10-07T18:03:12Z",
  "published": "2026-10-07T18:03:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/security/advisories/GHSA-qmw3-745m-w99g"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-106558"
    },
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/commit/32723a0fe4e12ed80535fc65d5331765c55aa91b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/commit/944edb51c8524d3664b18f2d57ba101b1c93b709"
    },
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/commit/f18e9abcc6051491862b15e4fc60e69f8d52310c"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/backstage/backstage"
    },
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/releases/tag/v1.50.7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/releases/tag/v1.54.9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/releases/tag/v1.55.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Backstage: Improper validation of TechDocs MkDocs configuration"
}

CVE-2026-106558 (GCVE-0-2026-106558)

Vulnerability from cvelistv5 – Published: 2026-10-07 14:45 – Updated: 2026-10-07 14:45

Title

Backstage: Improper validation of TechDocs MkDocs configuration

Summary

Backstage is an open framework for building developer portals. Prior to 1.14.8, 1.15.6, and 2.0.1, the @backstage/plugin-techdocs-node package improperly validated mapping-style markdown_extensions configuration. An authenticated attacker who can register or influence an SCM-backed documentation source may bypass TechDocs sanitization and cause Python objects to be imported and instantiated in the generator runtime, leading to arbitrary code execution. Earlier fixes in versions 1.14.6 and 1.15.4 did not fully address the supported mapping representation of markdown_extensions. Impact is greatest when documentation generation runs with backend credentials, filesystem access, or internal network access. This issue is fixed in versions 1.14.8, 1.15.6, and 2.0.1.

Severity

8.8 (High)


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

CWE

CWE-502 - Deserialization of Untrusted Data

Assigner

GitHub_M mitre root Scorecard

References

7 references

URL	Tags
https://github.com/backstage/backstage/security/a…	x_refsource_CONFIRM
https://github.com/backstage/backstage/commit/327…	x_refsource_MISC
https://github.com/backstage/backstage/commit/944…	x_refsource_MISC
https://github.com/backstage/backstage/commit/f18…	x_refsource_MISC
https://github.com/backstage/backstage/releases/t…	x_refsource_MISC
https://github.com/backstage/backstage/releases/t…	x_refsource_MISC
https://github.com/backstage/backstage/releases/t…	x_refsource_MISC

Impacted products

2 products

Vendor	Product	Version
backstage	backstage	Affected: < 1.50.7 Affected: >= 1.51.0-next.0, < 1.54.9 Affected: >= 1.55.0-next.0, < 1.55.2
@backstage	plugin-techdocs-node	Affected: < 1.14.8 Affected: >= 1.15.0, < 1.15.6 Affected: >= 2.0.0, < 2.0.1

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "backstage",
          "vendor": "backstage",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.50.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.51.0-next.0, \u003c 1.54.9"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.55.0-next.0, \u003c 1.55.2"
            }
          ]
        },
        {
          "product": "plugin-techdocs-node",
          "vendor": "@backstage",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.14.8"
            },
            {
              "status": "affected",
              "version": "\u003e= 1.15.0, \u003c 1.15.6"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.0.0, \u003c 2.0.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Backstage is an open framework for building developer portals. Prior to 1.14.8, 1.15.6, and 2.0.1, the @backstage/plugin-techdocs-node package improperly validated mapping-style markdown_extensions configuration. An authenticated attacker who can register or influence an SCM-backed documentation source may bypass TechDocs sanitization and cause Python objects to be imported and instantiated in the generator runtime, leading to arbitrary code execution. Earlier fixes in versions 1.14.6 and 1.15.4 did not fully address the supported mapping representation of markdown_extensions. Impact is greatest when documentation generation runs with backend credentials, filesystem access, or internal network access. This issue is fixed in versions 1.14.8, 1.15.6, and 2.0.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-502",
              "description": "CWE-502: Deserialization of Untrusted Data",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-07T14:45:25.679Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/backstage/backstage/security/advisories/GHSA-qmw3-745m-w99g",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/backstage/backstage/security/advisories/GHSA-qmw3-745m-w99g"
        },
        {
          "name": "https://github.com/backstage/backstage/commit/32723a0fe4e12ed80535fc65d5331765c55aa91b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/backstage/backstage/commit/32723a0fe4e12ed80535fc65d5331765c55aa91b"
        },
        {
          "name": "https://github.com/backstage/backstage/commit/944edb51c8524d3664b18f2d57ba101b1c93b709",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/backstage/backstage/commit/944edb51c8524d3664b18f2d57ba101b1c93b709"
        },
        {
          "name": "https://github.com/backstage/backstage/commit/f18e9abcc6051491862b15e4fc60e69f8d52310c",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/backstage/backstage/commit/f18e9abcc6051491862b15e4fc60e69f8d52310c"
        },
        {
          "name": "https://github.com/backstage/backstage/releases/tag/v1.50.7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/backstage/backstage/releases/tag/v1.50.7"
        },
        {
          "name": "https://github.com/backstage/backstage/releases/tag/v1.54.9",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/backstage/backstage/releases/tag/v1.54.9"
        },
        {
          "name": "https://github.com/backstage/backstage/releases/tag/v1.55.2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/backstage/backstage/releases/tag/v1.55.2"
        }
      ],
      "source": {
        "advisory": "GHSA-qmw3-745m-w99g",
        "discovery": "UNKNOWN"
      },
      "title": "Backstage: Improper validation of TechDocs MkDocs configuration"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-106558",
    "datePublished": "2026-10-07T14:45:25.679Z",
    "dateReserved": "2026-10-06T20:31:59.017Z",
    "dateUpdated": "2026-10-07T14:45:25.679Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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