Vulnerability-Lookup

ubuntu-cve-2026-73646

Vulnerability from osv_ubuntu

Published

2026-08-17 16:17

Modified

2026-08-19 11:11

Summary

Details

PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.18, lib/previous-map.js loadMap() passes attacker-controlled sourceMappingURL values to join(dirname(opts.from), annotation), and loadFile() permits traversed or absolute .map paths, allowing untrusted CSS processed without map: false to disclose sourcesContent from arbitrary reachable .map files through result.map. This issue is fixed in version 8.5.18.

Severity

7.5 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-73646	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-73646	REPORT
	https://github.com/postcss/postcss/security/advis…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-postcss",
            "binary_version": "6.0.23-3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "node-postcss",
        "purl": "pkg:deb/ubuntu/node-postcss@6.0.23-3?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "6.0.23-1",
        "6.0.23-3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-postcss",
            "binary_version": "8.4.6+~cs7.3.21-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "node-postcss",
        "purl": "pkg:deb/ubuntu/node-postcss@8.4.6+~cs7.3.21-1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.2.1+~cs5.3.23-8",
        "8.4.5+~cs7.1.51-2",
        "8.4.6+~cs7.3.21-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-postcss",
            "binary_version": "8.4.31+~cs8.0.26-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "node-postcss",
        "purl": "pkg:deb/ubuntu/node-postcss@8.4.31+~cs8.0.26-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.4.20+~cs8.0.23-1",
        "8.4.31+~cs8.0.26-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-postcss",
            "binary_version": "8.5.8+~cs9.3.30-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "node-postcss",
        "purl": "pkg:deb/ubuntu/node-postcss@8.5.8+~cs9.3.30-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.5.6+~cs9.3.28-1",
        "8.5.8+~cs9.3.30-1"
      ]
    }
  ],
  "aliases": [],
  "details": "PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.18, lib/previous-map.js loadMap() passes attacker-controlled sourceMappingURL values to join(dirname(opts.from), annotation), and loadFile() permits traversed or absolute .map paths, allowing untrusted CSS processed without map: false to disclose sourcesContent from arbitrary reachable .map files through result.map. This issue is fixed in version 8.5.18.",
  "id": "UBUNTU-CVE-2026-73646",
  "modified": "2026-08-19T11:11:14Z",
  "published": "2026-08-17T16:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-73646"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-73646"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-73646"
  ]
}

CVE-2026-73646 (GCVE-0-2026-73646)

Vulnerability from cvelistv5 – Published: 2026-08-17 15:35 – Updated: 2026-08-17 16:36

Title

PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure

Summary

Severity

7.5 (High)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-17 16:35 UTC

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/postcss/postcss/security/advis…	x_refsource_CONFIRM
https://github.com/postcss/postcss/commit/95663d3…	x_refsource_MISC
https://github.com/postcss/postcss/releases/tag/8.5.18	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
postcss	postcss	Affected: < 8.5.18

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-73646",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-17T16:35:17.036116Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-17T16:36:37.422Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "postcss",
          "vendor": "postcss",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 8.5.18"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "PostCSS takes a CSS file and provides an API to analyze and modify its rules by transforming the rules into an Abstract Syntax Tree. Prior to 8.5.18, lib/previous-map.js loadMap() passes attacker-controlled sourceMappingURL values to join(dirname(opts.from), annotation), and loadFile() permits traversed or absolute .map paths, allowing untrusted CSS processed without map: false to disclose sourcesContent from arbitrary reachable .map files through result.map. This issue is fixed in version 8.5.18."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T15:35:13.518Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/postcss/postcss/security/advisories/GHSA-r28c-9q8g-f849"
        },
        {
          "name": "https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/postcss/postcss/commit/95663d3eb7ba26f4854dd19d3b4f4425760cf56c"
        },
        {
          "name": "https://github.com/postcss/postcss/releases/tag/8.5.18",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/postcss/postcss/releases/tag/8.5.18"
        }
      ],
      "source": {
        "advisory": "GHSA-r28c-9q8g-f849",
        "discovery": "UNKNOWN"
      },
      "title": "PostCSS: Path Traversal in Previous Source Map Auto-Loading (sourceMappingURL) leads to Arbitrary .map File Disclosure"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-73646",
    "datePublished": "2026-08-17T15:35:13.518Z",
    "dateReserved": "2026-08-13T14:04:09.604Z",
    "dateUpdated": "2026-08-17T16:36:37.422Z",
    "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.

Detection rules are retrieved from Rulezet.

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.