Vulnerability-Lookup

CVE-2026-49401 (GCVE-0-2026-49401)

Vulnerability from cvelistv5 – Published: 2026-06-23 17:22 – Updated: 2026-07-31 13:15

Title

Deno Permission Bypass via Unicode Normalization Mismatch on macOS (APFS)

Summary

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno's permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done at the raw-byte level while the APFS filesystem treats different Unicode spellings of the same name as the same file. That means a program could reach a denied path by spelling it differently than the deny rule. This vulnerability is fixed in 2.7.14.

Severity

7.3 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-23 17:35 UTC

CWE

CWE-41 - Improper Resolution of Path Equivalence
CWE-176 - Improper Handling of Unicode Encoding

Assigner

GitHub_M mitre root

References

1 reference

URL	Tags
https://github.com/denoland/deno/security/advisor…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version	CPE status
denoland	deno	Affected: < 2.7.14	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-49401",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-23T17:35:46.438186Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-23T17:35:51.803Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "deno",
          "vendor": "denoland",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.7.14"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno\u0027s permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done at the raw-byte level while the APFS filesystem treats different Unicode spellings of the same name as the same file. That means a program could reach a denied path by spelling it differently than the deny rule. This vulnerability is fixed in 2.7.14."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 7.3,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-41",
              "description": "CWE-41: Improper Resolution of Path Equivalence",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-176",
              "description": "CWE-176: Improper Handling of Unicode Encoding",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-31T13:15:42.807Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/denoland/deno/security/advisories/GHSA-8xpq-cjcf-3wh9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/denoland/deno/security/advisories/GHSA-8xpq-cjcf-3wh9"
        }
      ],
      "source": {
        "advisory": "GHSA-8xpq-cjcf-3wh9",
        "discovery": "UNKNOWN"
      },
      "title": "Deno Permission Bypass via Unicode Normalization Mismatch on macOS (APFS)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-49401",
    "datePublished": "2026-06-23T17:22:32.266Z",
    "dateReserved": "2026-05-29T19:08:01.256Z",
    "dateUpdated": "2026-07-31T13:15:42.807Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-49401",
      "date": "2026-09-19",
      "epss": "0.00197",
      "percentile": "0.09724"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "deno",
                "vendor": "denoland",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 2.7.14"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:deno:deno:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "6D9303E8-C864-4B87-85A9-54A72C7DADEA",
                    "versionEndExcluding": "2.7.14",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              },
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:apple:macos:-:*:*:*:*:*:*:*",
                    "matchCriteriaId": "387021A0-AF36-463C-A605-32EA7DAC172E",
                    "vulnerable": false
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ],
            "operator": "AND"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno\u0027s permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done at the raw-byte level while the APFS filesystem treats different Unicode spellings of the same name as the same file. That means a program could reach a denied path by spelling it differently than the deny rule. This vulnerability is fixed in 2.7.14."
          }
        ],
        "id": "CVE-2026-49401",
        "lastModified": "2026-06-26T17:43:03.033",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "NONE",
                "baseScore": 7.3,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "LOW",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.0,
              "impactScore": 4.7,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "NONE",
                "baseScore": 8.4,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.0,
              "impactScore": 5.8,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-49401",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-23T17:35:46.438186Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-06-23T18:18:03.033",
        "references": [
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Exploit",
              "Mitigation",
              "Vendor Advisory"
            ],
            "url": "https://github.com/denoland/deno/security/advisories/GHSA-8xpq-cjcf-3wh9"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-41"
              },
              {
                "lang": "en",
                "value": "CWE-176"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-49401",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-06-23T17:35:46.438186Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-06-23T17:35:48.716Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "deno",
              "vendor": "denoland",
              "versions": [
                {
                  "status": "affected",
                  "version": "\u003c 2.7.14"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno\u0027s permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done at the raw-byte level while the APFS filesystem treats different Unicode spellings of the same name as the same file. That means a program could reach a denied path by spelling it differently than the deny rule. This vulnerability is fixed in 2.7.14."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "NONE",
                "baseScore": 7.3,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "LOW",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N",
                "version": "3.1"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-41",
                  "description": "CWE-41: Improper Resolution of Path Equivalence",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            },
            {
              "descriptions": [
                {
                  "cweId": "CWE-176",
                  "description": "CWE-176: Improper Handling of Unicode Encoding",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-07-31T13:15:42.807Z",
            "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
            "shortName": "GitHub_M"
          },
          "references": [
            {
              "name": "https://github.com/denoland/deno/security/advisories/GHSA-8xpq-cjcf-3wh9",
              "tags": [
                "x_refsource_CONFIRM"
              ],
              "url": "https://github.com/denoland/deno/security/advisories/GHSA-8xpq-cjcf-3wh9"
            }
          ],
          "source": {
            "advisory": "GHSA-8xpq-cjcf-3wh9",
            "discovery": "UNKNOWN"
          },
          "title": "Deno Permission Bypass via Unicode Normalization Mismatch on macOS (APFS)"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-49401",
        "datePublished": "2026-06-23T17:22:32.266Z",
        "dateReserved": "2026-05-29T19:08:01.256Z",
        "dateUpdated": "2026-07-31T13:15:42.807Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-49401

Vulnerability from fkie_nvd - Published: 2026-06-23 18:18 - Updated: 2026-06-26 17:43

Severity

7.3 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N
8.4 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/denoland/deno/security/advisories/GHSA-8xpq-cjcf-3wh9	Exploit, Mitigation, Vendor Advisory

Impacted products

	Vendor	Product	Version
	deno	deno	*
	apple	macos	-

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "deno",
          "vendor": "denoland",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.7.14"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:deno:deno:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "6D9303E8-C864-4B87-85A9-54A72C7DADEA",
              "versionEndExcluding": "2.7.14",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        },
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:apple:macos:-:*:*:*:*:*:*:*",
              "matchCriteriaId": "387021A0-AF36-463C-A605-32EA7DAC172E",
              "vulnerable": false
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ],
      "operator": "AND"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.14, Deno\u0027s permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done at the raw-byte level while the APFS filesystem treats different Unicode spellings of the same name as the same file. That means a program could reach a denied path by spelling it differently than the deny rule. This vulnerability is fixed in 2.7.14."
    }
  ],
  "id": "CVE-2026-49401",
  "lastModified": "2026-06-26T17:43:03.033",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 7.3,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 4.7,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 8.4,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.0,
        "impactScore": 5.8,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-49401",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-23T17:35:46.438186Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-23T18:18:03.033",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/denoland/deno/security/advisories/GHSA-8xpq-cjcf-3wh9"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-41"
        },
        {
          "lang": "en",
          "value": "CWE-176"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

GHSA-8XPQ-CJCF-3WH9

Vulnerability from github – Published: 2026-06-16 19:11 – Updated: 2026-07-31 13:15

Summary

Deno: Permission Bypass via Unicode Normalization Mismatch on macOS (APFS)

Details

Summary

Deno's permission system enforces filesystem and execution restrictions by comparing the requested path against the path supplied to --deny-read, --deny-write, --deny-run, or --deny-ffi. On macOS, that comparison was done at the raw-byte level while the APFS filesystem treats different Unicode spellings of the same name as the same file.

That means a program could reach a denied path by spelling it differently than the deny rule. For example, with --deny-read=/secrets/passwörter.txt, a script could still read the file by opening /secrets/passwo\u0308rter.txt (NFD instead of NFC), or /SECRETS/PASSWÖRTER.txt (different case, since default APFS volumes are case-insensitive). Other forms include ligature characters (ﬁ vs fi, ﬀ vs ff, …) and German ß vs ss.

The denied path and the requested path differed at the byte level, so Deno's permission check passed; the kernel then resolved them to the same inode and served the file anyway. The same flaw affected --deny-write, --deny-run, and --deny-ffi, which share the same path-comparison code.

Am I affected?

You are potentially affected if all of the following are true:

You run Deno on macOS (the issue is specific to APFS path-equivalence rules; Linux and Windows are not affected by this variant).
You rely on --deny-read, --deny-write, --deny-run, or --deny-ffi as a security boundary against less-trusted code — a dependency, plugin, or attacker-controlled input.
The protected path contains characters that have alternate Unicode spellings — most commonly accented characters (é, ñ, ö, …), German ß, or Latin ligatures — or you rely on case-sensitivity on a default APFS volume.

If you only run fully trusted code, or your deny rules cover paths that are pure ASCII with no case-sensitive aliases, you are not exposed to this specific bypass.

Impact

A program running with broad --allow-read (or --allow-write / --allow-run / --allow-ffi) but with --deny-* carve-outs for specific paths could read, write, execute, or load via FFI those denied paths by referring to them through a Unicode- or case-equivalent spelling. The sandbox model on macOS was weaker than the flags suggested.

Workaround

If you cannot upgrade immediately:

Prefer --allow-* allowlists over --deny-* denylists. Allow rules match against the original specifier, so an attacker-supplied alternate spelling will not match a path you didn't explicitly grant.
Do not rely on case-sensitivity of paths on macOS for security boundaries; default APFS volumes are case-insensitive.

Fix

On macOS, Deno now normalizes both the deny-rule path and the requested path to NFC and applies Unicode case folding before comparing them. This matches how APFS resolves paths at the inode level, so byte-different but equivalent spellings are now rejected by the same deny rule.

Severity

7.3 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.7.13"
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "deno"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.7.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49401"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-176",
      "CWE-41"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-16T19:11:52Z",
    "nvd_published_at": "2026-06-23T18:18:03Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nDeno\u0027s permission system enforces filesystem and execution restrictions by\ncomparing the requested path against the path supplied to `--deny-read`,\n`--deny-write`, `--deny-run`, or `--deny-ffi`. On macOS, that comparison was\ndone at the raw-byte level while the APFS filesystem treats different Unicode\nspellings of the same name as the same file.\n\nThat means a program could reach a denied path by spelling it differently than\nthe deny rule. For example, with `--deny-read=/secrets/passw\u00f6rter.txt`, a\nscript could still read the file by opening `/secrets/passwo\\u0308rter.txt`\n(NFD instead of NFC), or `/SECRETS/PASSW\u00d6RTER.txt` (different case, since\ndefault APFS volumes are case-insensitive). Other forms include ligature\ncharacters (`\ufb01` vs `fi`, `\ufb00` vs `ff`, \u2026) and German `\u00df` vs `ss`.\n\nThe denied path and the requested path differed at the byte level, so Deno\u0027s\npermission check passed; the kernel then resolved them to the same inode and\nserved the file anyway. The same flaw affected `--deny-write`, `--deny-run`,\nand `--deny-ffi`, which share the same path-comparison code.\n\n## Am I affected?\n\nYou are potentially affected if **all** of the following are true:\n\n1. You run Deno on **macOS** (the issue is specific to APFS path-equivalence\n   rules; Linux and Windows are not affected by this variant).\n2. You rely on `--deny-read`, `--deny-write`, `--deny-run`, or `--deny-ffi`\n   as a security boundary against less-trusted code \u2014 a dependency, plugin,\n   or attacker-controlled input.\n3. The protected path contains characters that have alternate Unicode\n   spellings \u2014 most commonly accented characters (`\u00e9`, `\u00f1`, `\u00f6`, \u2026), German\n   `\u00df`, or Latin ligatures \u2014 or you rely on case-sensitivity on a default\n   APFS volume.\n\nIf you only run fully trusted code, or your deny rules cover paths that are\npure ASCII with no case-sensitive aliases, you are not exposed to this\nspecific bypass.\n\n## Impact\n\nA program running with broad `--allow-read` (or `--allow-write` /\n`--allow-run` / `--allow-ffi`) but with `--deny-*` carve-outs for specific\npaths could read, write, execute, or load via FFI those denied paths by\nreferring to them through a Unicode- or case-equivalent spelling. The sandbox\nmodel on macOS was weaker than the flags suggested.\n\n## Workaround\n\nIf you cannot upgrade immediately:\n\n- Prefer `--allow-*` allowlists over `--deny-*` denylists. Allow rules match\n   against the original specifier, so an attacker-supplied alternate spelling\n   will not match a path you didn\u0027t explicitly grant.\n- Do not rely on case-sensitivity of paths on macOS for security boundaries;\n   default APFS volumes are case-insensitive.\n\n## Fix\n\nOn macOS, Deno now normalizes both the deny-rule path and the requested path\nto NFC and applies Unicode case folding before comparing them. This matches\nhow APFS resolves paths at the inode level, so byte-different but equivalent\nspellings are now rejected by the same deny rule.",
  "id": "GHSA-8xpq-cjcf-3wh9",
  "modified": "2026-07-31T13:15:54Z",
  "published": "2026-06-16T19:11:52Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/denoland/deno/security/advisories/GHSA-8xpq-cjcf-3wh9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-49401"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/denoland/deno"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Deno: Permission Bypass via Unicode Normalization Mismatch on macOS (APFS)"
}

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.

Action not permitted

CVE-2026-49401 (GCVE-0-2026-49401)

FKIE_CVE-2026-49401

GHSA-8XPQ-CJCF-3WH9

Summary

Am I affected?

Impact

Workaround

Fix

Tags

Sightings

Nomenclature

Related by attack behaviour