CVE-2026-15806
published 2026-08-18CVE-2026-15806: The HTTPPasswordMgr class in the urllib.request module, along with its subclasses HTTPPasswordMgrWithDefaultRealm and HTTPPasswordMgrWithPriorAuth, did not…
PriorityP337medium6CVSS 4.0
AVNACHATPPRNUIPVCHVINVANSCNSINSANEXCRXIRXARXMAVXMACXMATXMPRXMUIXMVCXMVIXMVAXMSCXMSIXMSAXSXAUXRXVXREXUX
EPSS
0.53%
43.9th percentile
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.
Affected
6 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| python_software_foundation | cpython | < 3.10.22 | 3.10.22 |
| python_software_foundation | cpython | >= 3.11.0 < 3.11.17 | 3.11.17 |
| python_software_foundation | cpython | >= 3.12.0 < 3.12.15 | 3.12.15 |
| python_software_foundation | cpython | >= 3.13.0 < 3.13.16 | 3.13.16 |
| python_software_foundation | cpython | >= 3.14.0 < 3.14.8 | 3.14.8 |
| python_software_foundation | cpython | >= 3.15.0a1 < 3.15.0rc2 | 3.15.0rc2 |
CVSS provenance
nvdv4.06.0MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat6.0MEDIUM
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Red Hat
python: Python: Information disclosure due to incorrect URL scheme matching
vendor_redhat·2026-08-18·CVSS 6.0
CVE-2026-15806 [MEDIUM] CWE-420 python: Python: Information disclosure due to incorrect URL scheme matching
python: Python: Information disclosure due to incorrect URL scheme matching
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 reques
VulDB
PSF Python up to 3.15.x urllib.request HTTPPasswordMgr missing encryption (EUVD-2026-61013 / Nessus ID 364204)
vuldb·2026-10-08·CVSS 6.0
CVE-2026-15806 [MEDIUM] PSF Python up to 3.15.x urllib.request HTTPPasswordMgr missing encryption (EUVD-2026-61013 / Nessus ID 364204)
A vulnerability classified as problematic was found in PSF Python up to 3.15.x. The affected element is the function HTTPPasswordMgr of the component urllib.request. Executing a manipulation can lead to missing encryption of sensitive data.
The identification of this vulnerability is CVE-2026-15806. The attack may be launched remotely. There is no exploit available.
Upgrading the affected component is advised.
GHSA
The HTTPPasswordMgr class in the urllib.request module, along with its subclasses HTTPPasswordMgrWithDefaultRealm and HTTPPasswordMgrWithPriorAuth, did not take the URL scheme into account when matchi
ghsa_unreviewed·2026-08-18
CVE-2026-15806 [MEDIUM] CWE-319 The HTTPPasswordMgr class in the urllib.request module, along with its subclasses HTTPPasswordMgrWithDefaultRealm and HTTPPasswordMgrWithPriorAuth, did not take the URL scheme into account when matchi
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
No detection rules found.
No public exploits indexed.
https://github.com/python/cpython/commit/641be42bb07921ba0f8bffe228b1dc706b092ef6https://github.com/python/cpython/commit/851cf9a7142ecbdd39f831055533f58284ad2bcchttps://github.com/python/cpython/commit/95355ee3a8e1d3c3d4858d1973aa42a9b91a2801https://github.com/python/cpython/commit/a0d023fbd23773e24b35d8368789470e22cda5d8https://github.com/python/cpython/commit/a2773a34183b7d94a243bb98fd658926cc5348cehttps://github.com/python/cpython/commit/a7bb524fef61f77ede01f660ffbd591e1d5837cehttps://github.com/python/cpython/commit/dac88d8615078c55f1304ea4c7a2d822700d4e5ahttps://github.com/python/cpython/issues/155694https://github.com/python/cpython/pull/155696https://mail.python.org/archives/list/[email protected]/thread/3OKPE5S75KDNA7FY7AI3PL2MXM2X5RB3/http://www.openwall.com/lists/oss-security/2026/08/18/3https://github.com/python/cpython/issues/155694
2026-08-18
Published