CVE-2026-15806
Publication date 18 August 2026
Last updated 2 September 2026
Ubuntu priority
Description
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| python2.7 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
|
| 14.04 LTS trusty |
Needs evaluation
|
|
| python3.4 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 14.04 LTS trusty |
Needs evaluation
|
|
| python3.5 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 16.04 LTS xenial |
Needs evaluation
|
|
| 14.04 LTS trusty |
Needs evaluation
|
|
| python3.6 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 18.04 LTS bionic |
Needs evaluation
|
|
| python3.7 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 18.04 LTS bionic |
Needs evaluation
|
|
| python3.8 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| python3.9 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 20.04 LTS focal |
Needs evaluation
|
|
| python3.10 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy |
Needs evaluation
|
|
| python3.11 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy |
Needs evaluation
|
|
| python3.12 | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy | Not in release | |
| python3.14 | 26.04 LTS resolute |
Needs evaluation
|
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release |
Severity score breakdown
CVSS version: CVSS v4.0
Base score
6.0 · Medium
Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N