PSF Python up to 3.15.x urllib.request HTTPPasswordMgr missing encryption

Summaryinfo

A vulnerability, which was classified as problematic, has been found in PSF Python up to 3.15.x. The impacted element is the function HTTPPasswordMgr of the component urllib.request. The manipulation leads to missing encryption. This vulnerability is referenced as CVE-2026-15806. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in PSF Python up to 3.15.x. It has been rated as problematic. This issue affects the function HTTPPasswordMgr of the component urllib.request. The manipulation with an unknown input leads to a missing encryption vulnerability. Using CWE to declare the problem leads to CWE-311. The product does not encrypt sensitive or critical information before storage or transmission. Impacted is confidentiality. The summary by CVE is:

The HTTPPasswordMgr class in the urllib.request module, along with its subclasses HTTPPasswordMgrWithDefaultRealm and HTTPPasswordMgrWithPriorAuth, did not take the URL scheme into account when matching stored credentials against a requested URL. Credentials added for an https:// URL were also used for requests to the same host over http://, so an attacker able to redirect or downgrade a client to plain HTTP (for example, via an HTTPS-to-HTTP redirect or an on-path position) could capture credentials in cleartext. Credentials added for http:// URLs could likewise be sent over https://. Credential matching is now scoped by URL scheme. Credentials registered with a URL that includes a scheme are only used for requests with the same scheme. Credentials registered with a bare authority (such as example.com or example.com:8080) continue to match any scheme, preserving compatibility with existing code, including proxy authentication. Users who cannot upgrade immediately can mitigate by ensuring that applications never make plain http:// requests to hosts for which credentials are registered, for example by not following redirects to http:// URLs.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-15806 since 07/15/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1600 for this issue.

Upgrading to version 3.16.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at EUVD (EUVD-2026-61013) and CERT Bund (WID-SEC-2026-2924). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• Open Source Python

Productinfo

Type

• Programming Language Software

Vendor

• PSF

Name

• Python

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
• 3.13
• 3.14
• 3.15

License

• open-source

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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