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Fencer Vulns
medium 6.0

CVE-2026-15806 json

`HTTPPasswordMgr` can send saved HTTPS credentials via HTTP because of incorrect scheme matching

published 2026-08-18 2 mo ago modified 2026-10-22 17 d ago also BIT-libpython-2026-15806 , BIT-python-2026-15806 , BIT-python-min-2026-15806 , EUVD-2026-61013

cvss
6.0
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami libpython 3.10.22, 3.11.17, 3.12.15, 3.13.16, 3.14.8
  • bitnami python 3.10.22, 3.11.17, 3.12.15, 3.13.16, 3.14.8
  • bitnami python-min 3.10.22, 3.11.17, 3.12.15, 3.13.16, 3.14.8
  • Python Software Foundation CPython 3.10.22, 3.11.17, 3.12.15, 3.13.16, 3.14.8, 3.15.0rc2
  • pypy3 Debian 14 8.0.1+dfsg-1
  • python3.11 Debian 12 3.11.2-6+deb12u9
  • python3.14 Debian 14 3.14.7-3
  • python3.15 Debian 14 3.15.0~rc2-1

debian advisories DEBIAN-CVE-2026-15806

  • python3.13 hummingbird 1 3.13.15-1.1.hum1
  • python3.13-idle hummingbird 1 3.13.15-1.1.hum1
  • python3.13-libs hummingbird 1 3.13.15-1.1.hum1
  • python3.13-test hummingbird 1 3.13.15-1.1.hum1
  • python3.13-tkinter hummingbird 1 3.13.15-1.1.hum1
  • python3.13-freethreading hummingbird 1 3.13.15-1.1.hum1
  • python3.12 hummingbird 1 3.12.14-1.1.hum1
  • python3.12-idle hummingbird 1 3.12.14-1.1.hum1

red hat advisories RHSA-2026:65567RHSA-2026:65531RHSA-2026:65525RHSA-2026:65513RHSA-2026:65505

  • python311 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Python 3 15 SP7 3.11.17-150600.3.74.1
  • python311-core SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Python 3 15 SP7 +1 more 3.11.17-150600.3.74.1
  • python313 SLE Module for Python 3 15 SP7 3.13.16-150700.4.61.1
  • python313-core SLE Module for Python 3 15 SP7 3.13.16-150700.4.61.1
  • python311 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +6 more 3.11.17-150400.9.105.1
  • python311-core SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +6 more 3.11.17-150400.9.105.1
  • python311-documentation SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 3.11.17-150400.9.105.1
  • python3 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +11 more 3.6.15-150300.10.129.1

suse advisories SUSE-SU-2026:4946-1SUSE-SU-2026:4941-1SUSE-SU-2026:4809-1SUSE-SU-2026:4754-1SUSE-SU-2026:4744-1SUSE-SU-2026:4743-1

  • python313 openSUSE Tumbleweed 3.13.16-1.1
  • python314 openSUSE Tumbleweed 3.14.8-1.1
  • python312 openSUSE Tumbleweed 3.12.14-2.1
  • python310 openSUSE Tumbleweed 3.10.21-2.1
  • python311 openSUSE Tumbleweed 3.11.16-2.1
  • python315 openSUSE Tumbleweed 3.15.0~rc2-1.1

opensuse advisories openSUSE-SU-2026:12123-1openSUSE-SU-2026:12124-1openSUSE-SU-2026:11975-1openSUSE-SU-2026:11949-1openSUSE-SU-2026:11886-1openSUSE-SU-2026:11748-1

  • python3 Alpine 3.23, Alpine 3.22, Alpine 3.21 3.12.15-r0
  • python3 Alpine 3.24 3.14.8-r0

alpine advisories ALPINE-CVE-2026-15806

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python3 Azure Linux 3.0 3.12.14-2

azure linux advisories AZL-96867

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-15806 updated cvss 5.3

python: Python: Information disclosure due to incorrect URL scheme matching

  • Red Hat Hardened Images python3 3.14.7-1.1.hum1, python3.14 3.14.7-1.1.hum1, python3.10 3.10.21-1.1.hum1, python3.11 3.11.16-1.2.hum1, python3.12 3.12.14-1.1.hum1, python3.13 3.13.15-1.1.hum1, +1 more
    fixed: vendor fix RHSA-2026:65513
  • Red Hat Hardened Images hi/python
    not affected: component not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/python/cpython/issues/155694 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 6.0 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
CNA 4.0 6.0 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/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

Affected packages

ecosystem package affected fixed in
bitnami libpython
<3.10.22
>=3.11.0, <3.11.17
>=3.12.0, <3.12.15
>=3.13.0, <3.13.16
>=3.14.0, <3.14.8
3.10.22
3.11.17
3.12.15
3.13.16
3.14.8
bitnami python
<3.10.22
>=3.11.0, <3.11.17
>=3.12.0, <3.12.15
>=3.13.0, <3.13.16
>=3.14.0, <3.14.8
3.10.22
3.11.17
3.12.15
3.13.16
3.14.8
bitnami python-min
<3.10.22
>=3.11.0, <3.11.17
>=3.12.0, <3.12.15
>=3.13.0, <3.13.16
>=3.14.0, <3.14.8
3.10.22
3.11.17
3.12.15
3.13.16
3.14.8

Affected products

  • Python Software Foundation CPython

Classification

Weakness
  • CWE-319 Cleartext Transmission of Sensitive Information
  • CWE-522 Insufficiently Protected Credentials

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.