CVE-2026-21860

Werkzeug is a comprehensive WSGI web application library. Prior to version 3.1.5, Werkzeug's safe_join function allows path segments with Windows device names that have file extensions or trailing spaces. On Windows, there are special device names such as CON, AUX, etc that are implicitly present and readable in every directory. Windows still accepts them with any file extension, such as CON.txt, or trailing spaces such as CON. This issue has been patched in version 3.1.5.

Database specific

{
    "cwe_ids": [
        "CWE-67"
    ],
    "cna_assigner": "GitHub_M",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21860.json"
}

References

Affected packages

Git / github.com/pallets/werkzeug

Affected ranges

Type: GIT
Repo: https://github.com/pallets/werkzeug
Events: Introduced

0 Unknown introduced commit / All previous commits are affected

Fixed

e3d06f4b1f7ff40a63eba78f81d9cda18f805d6d

Affected versions

0.*

0.1

0.10

0.10.1

0.10.2

0.10.3

0.10.4

0.11

0.11.1

0.11.10

0.11.11

0.11.12

0.11.13

0.11.14

0.11.15

0.11.2

0.11.3

0.11.4

0.11.5

0.11.6

0.11.7

0.11.8

0.11.9

0.12

0.12.1

0.12.2

0.13

0.14

0.14.1

0.14.x

0.15.0

0.15.1

0.15.2

0.15.3

0.15.4

0.15.5

0.15.6

0.15.x

0.16.0

0.16.1

0.16.x

0.2

0.3

0.3.1

0.4

0.4.1

0.5

0.5.1

0.6

0.6.1

0.6.2

0.7

0.8

0.8.1

0.8.2

0.8.3

0.9

0.9.1

0.9.2

0.9.3

0.9.4

0.9.5

0.9.6

1.*

1.0.0

1.0.0rc1

1.0.1

1.0.x

2.*

2.0.0

2.0.0rc1

2.0.0rc2

2.0.0rc3

2.0.0rc4

2.0.0rc5

2.0.1

2.0.2

2.0.3

2.0.x

2.1.0

2.1.1

2.1.2

2.1.x

2.2.0

2.2.0a1

2.2.1

2.2.2

2.2.3

2.2.x

2.3.0

2.3.1

2.3.2

2.3.3

2.3.4

2.3.5

2.3.6

2.3.7

2.3.8

2.3.x

3.*

3.0.2

3.0.3

3.0.4

3.0.5

3.0.6

3.0.x

3.1.0

3.1.1

3.1.2

3.1.3

3.1.4

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-21860.json"