CVE-2026-25766 (GCVE-0-2026-25766)

Vulnerability from cvelistv5 – Published: 2026-02-19 15:49 – Updated: 2026-02-19 19:46
VLAI
Title
Echo has a Windows path traversal via backslash in middleware.Static default filesystem
Summary
Echo is a Go web framework. In versions 5.0.0 through 5.0.2 on Windows, Echo’s `middleware.Static` using the default filesystem allows path traversal via backslashes, enabling unauthenticated remote file read outside the static root. In `middleware/static.go`, the requested path is unescaped and normalized with `path.Clean` (URL semantics). `path.Clean` does not treat `\` as a path separator, so `..\` sequences remain in the cleaned path. The resulting path is then passed to `currentFS.Open(...)`. When the filesystem is left at the default (nil), Echo uses `defaultFS` which calls `os.Open` (`echo.go:792`). On Windows, `os.Open` treats `\` as a path separator and resolves `..\`, allowing traversal outside the static root. Version 5.0.3 fixes the issue.
Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-02-19 19:45 UTC
CWE
  • CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Assigner
References
Impacted products
Vendor Product Version CPE status
labstack echo Affected: >= 5.0.0, < 5.0.3
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-25766",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-19T19:45:33.220477Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-19T19:46:01.829Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "echo",
          "vendor": "labstack",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 5.0.0, \u003c 5.0.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Echo is a Go web framework. In versions 5.0.0 through 5.0.2 on Windows, Echo\u2019s `middleware.Static` using the default filesystem allows path traversal via backslashes, enabling unauthenticated remote file read outside the static root. In `middleware/static.go`, the requested path is unescaped and normalized with `path.Clean` (URL semantics). `path.Clean` does not treat `\\` as a path separator, so `..\\` sequences remain in the cleaned path. The resulting path is then passed to `currentFS.Open(...)`. When the filesystem is left at the default (nil), Echo uses `defaultFS` which calls `os.Open` (`echo.go:792`). On Windows, `os.Open` treats `\\` as a path separator and resolves `..\\`, allowing traversal outside the static root. Version 5.0.3 fixes the issue."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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": "2026-02-19T15:49:02.402Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/labstack/echo/security/advisories/GHSA-pgvm-wxw2-hrv9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/labstack/echo/security/advisories/GHSA-pgvm-wxw2-hrv9"
        },
        {
          "name": "https://github.com/labstack/echo/pull/2891",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/labstack/echo/pull/2891"
        },
        {
          "name": "https://github.com/labstack/echo/commit/b1d443086ea27cf51345ec72a71e9b7e9d9ce5f1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/labstack/echo/commit/b1d443086ea27cf51345ec72a71e9b7e9d9ce5f1"
        }
      ],
      "source": {
        "advisory": "GHSA-pgvm-wxw2-hrv9",
        "discovery": "UNKNOWN"
      },
      "title": "Echo has a Windows path traversal via backslash in middleware.Static default filesystem"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-25766",
    "datePublished": "2026-02-19T15:49:02.402Z",
    "dateReserved": "2026-02-05T18:35:52.358Z",
    "dateUpdated": "2026-02-19T19:46:01.829Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-25766",
      "date": "2026-09-21",
      "epss": "0.00342",
      "percentile": "0.27741"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "echo",
                "vendor": "labstack",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003e= 5.0.0, \u003c 5.0.3"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:labstack:echo:*:*:*:*:*:go:*:*",
                    "matchCriteriaId": "27FD7D9D-DB8A-4CC1-8024-72E6C1865D46",
                    "versionEndExcluding": "5.0.3",
                    "versionStartIncluding": "5.0.0",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              },
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*",
                    "matchCriteriaId": "A2572D17-1DE6-457B-99CC-64AFD54487EA",
                    "vulnerable": false
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ],
            "operator": "AND"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "Echo is a Go web framework. In versions 5.0.0 through 5.0.2 on Windows, Echo\u2019s `middleware.Static` using the default filesystem allows path traversal via backslashes, enabling unauthenticated remote file read outside the static root. In `middleware/static.go`, the requested path is unescaped and normalized with `path.Clean` (URL semantics). `path.Clean` does not treat `\\` as a path separator, so `..\\` sequences remain in the cleaned path. The resulting path is then passed to `currentFS.Open(...)`. When the filesystem is left at the default (nil), Echo uses `defaultFS` which calls `os.Open` (`echo.go:792`). On Windows, `os.Open` treats `\\` as a path separator and resolves `..\\`, allowing traversal outside the static root. Version 5.0.3 fixes the issue."
          },
          {
            "lang": "es",
            "value": "Echo es un marco web de Go. En las versiones 5.0.0 a 5.0.2 en Windows, el `middleware.Static` de Echo que utiliza el sistema de archivos predeterminado permite recorrer rutas mediante barras invertidas, lo que permite la lectura de archivos remotos no autenticados fuera de la ra\u00edz est\u00e1tica. En `middleware/static.go`, la ruta solicitada no se escapa y se normaliza con `path.Clean` (sem\u00e1ntica de URL). `path.Clean` no trata `\\` como un separador de ruta, por lo que las secuencias `..\\` permanecen en la ruta limpia. La ruta resultante se pasa entonces a `currentFS.Open(...)`. Cuando el sistema de archivos se deja en el valor predeterminado (nil), Echo utiliza `defaultFS`, que llama a `os.Open` (`echo.go:792`). En Windows, `os.Open` trata `\\` como un separador de ruta y resuelve `..\\`, lo que permite el recorrido fuera de la ra\u00edz est\u00e1tica. La versi\u00f3n 5.0.3 corrige el problema."
          }
        ],
        "id": "CVE-2026-25766",
        "lastModified": "2026-06-17T10:25:11.797",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 1.4,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-25766",
                "options": [
                  {
                    "exploitation": "poc"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-19T19:45:33.220477Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-02-19T16:27:15.497",
        "references": [
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Patch"
            ],
            "url": "https://github.com/labstack/echo/commit/b1d443086ea27cf51345ec72a71e9b7e9d9ce5f1"
          },
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Issue Tracking",
              "Patch"
            ],
            "url": "https://github.com/labstack/echo/pull/2891"
          },
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Exploit",
              "Vendor Advisory"
            ],
            "url": "https://github.com/labstack/echo/security/advisories/GHSA-pgvm-wxw2-hrv9"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-22"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-02-20T19:40:24+00:00",
      "cve": "CVE-2026-25766",
      "id": "CVE-2026-25766",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "Echo has a Windows path traversal via backslash in middleware.Static default filesystem",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25766.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-25766",
                    "options": [
                      {
                        "Exploitation": "poc"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-02-19T19:45:33.220477Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-02-19T19:45:56.146Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "echo",
              "vendor": "labstack",
              "versions": [
                {
                  "status": "affected",
                  "version": "\u003e= 5.0.0, \u003c 5.0.3"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "Echo is a Go web framework. In versions 5.0.0 through 5.0.2 on Windows, Echo\u2019s `middleware.Static` using the default filesystem allows path traversal via backslashes, enabling unauthenticated remote file read outside the static root. In `middleware/static.go`, the requested path is unescaped and normalized with `path.Clean` (URL semantics). `path.Clean` does not treat `\\` as a path separator, so `..\\` sequences remain in the cleaned path. The resulting path is then passed to `currentFS.Open(...)`. When the filesystem is left at the default (nil), Echo uses `defaultFS` which calls `os.Open` (`echo.go:792`). On Windows, `os.Open` treats `\\` as a path separator and resolves `..\\`, allowing traversal outside the static root. Version 5.0.3 fixes the issue."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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": "2026-02-19T15:49:02.402Z",
            "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
            "shortName": "GitHub_M"
          },
          "references": [
            {
              "name": "https://github.com/labstack/echo/security/advisories/GHSA-pgvm-wxw2-hrv9",
              "tags": [
                "x_refsource_CONFIRM"
              ],
              "url": "https://github.com/labstack/echo/security/advisories/GHSA-pgvm-wxw2-hrv9"
            },
            {
              "name": "https://github.com/labstack/echo/pull/2891",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/labstack/echo/pull/2891"
            },
            {
              "name": "https://github.com/labstack/echo/commit/b1d443086ea27cf51345ec72a71e9b7e9d9ce5f1",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/labstack/echo/commit/b1d443086ea27cf51345ec72a71e9b7e9d9ce5f1"
            }
          ],
          "source": {
            "advisory": "GHSA-pgvm-wxw2-hrv9",
            "discovery": "UNKNOWN"
          },
          "title": "Echo has a Windows path traversal via backslash in middleware.Static default filesystem"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-25766",
        "datePublished": "2026-02-19T15:49:02.402Z",
        "dateReserved": "2026-02-05T18:35:52.358Z",
        "dateUpdated": "2026-02-19T19:46:01.829Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


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.