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TI-2021-09843 Aliases CVE-2021-28861GHSA-h7f6-hc46-frrv

Python 3.x through 3.10 has an open redirection vulnerability in lib/http/server.py due…

Priority LOW 37CWE-601Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Spoofing
Confidentiality · integrity · availability
High · None · None
Fix status
Partial Red Hat: 8 fixed, 2 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-601.

Summary

Python 3.x through 3.10 has an open redirection vulnerability in lib/http/server.py due to no protection against multiple (/) at the beginning of URI path which may leads to information disclosure. NOTE: this is disputed by a third party because the http.server.html documentation page states "Warning: http.server is not recommended for production. It only implements basic security checks."

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.02683 85th percentileScored 2026-11-07
Fix Partial Red Hat: 5 advisoriesRed Hat: 8 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 14

CPEVersionsRoleVendor
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*3.0.0 to before 3.7.14; 3.8.0 to before 3.8.14; 3.9.0 to before 3.9.14; 3.10.0 to before 3.10.6Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:alpha1:*:*:*:*:*:*3.11.0 alpha1Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:alpha2:*:*:*:*:*:*3.11.0 alpha2Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:alpha3:*:*:*:*:*:*3.11.0 alpha3Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:alpha4:*:*:*:*:*:*3.11.0 alpha4Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:alpha5:*:*:*:*:*:*3.11.0 alpha5Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:alpha6:*:*:*:*:*:*3.11.0 alpha6Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:alpha7:*:*:*:*:*:*3.11.0 alpha7Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:beta1:*:*:*:*:*:*3.11.0 beta1Vulnerablepython-pillow
cpe:2.3:a:python:python:3.11.0:beta2:*:*:*:*:*:*3.11.0 beta2Vulnerablepython-pillow
  • cpe:2.3:a:python:python:*:*:*:*:*:*:*:* Versions 3.0.0 to before 3.7.14; 3.8.0 to before 3.8.14; 3.9.0 to before 3.9.14; 3.10.0 to before 3.10.6 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:alpha1:*:*:*:*:*:* Versions 3.11.0 alpha1 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:alpha2:*:*:*:*:*:* Versions 3.11.0 alpha2 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:alpha3:*:*:*:*:*:* Versions 3.11.0 alpha3 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:alpha4:*:*:*:*:*:* Versions 3.11.0 alpha4 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:alpha5:*:*:*:*:*:* Versions 3.11.0 alpha5 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:alpha6:*:*:*:*:*:* Versions 3.11.0 alpha6 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:alpha7:*:*:*:*:*:* Versions 3.11.0 alpha7 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:beta1:*:*:*:*:*:* Versions 3.11.0 beta1 Vulnerable ·python-pillow
  • cpe:2.3:a:python:python:3.11.0:beta2:*:*:*:*:*:* Versions 3.11.0 beta2 Vulnerable ·python-pillow
Show 4 more CPE
CPEVersionsRoleVendor
cpe:2.3:a:python:python:3.11.0:beta3:*:*:*:*:*:*3.11.0 beta3Vulnerablepython-pillow
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*35VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*36VulnerableFedoraproject
cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*37VulnerableFedoraproject
  • cpe:2.3:a:python:python:3.11.0:beta3:*:*:*:*:*:* Versions 3.11.0 beta3 Vulnerable ·python-pillow
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* Versions 36 Vulnerable ·Fedoraproject
  • cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:* Versions 37 Vulnerable ·Fedoraproject

Remediation

Red Hat 5 advisories

  • RHSA-2023:2763 Released 2023-05-16 · Red Hat rating Moderate
    python38:3.8 and python38-devel:3.8 security update
    • Red Hat Enterprise Linux AppStream (v. 8) Cython-0.29.14-4.module+el8.4.0+8888+89bc7e79.src::python38:3.8, PyYAML-5.4.1-1.module+el8.5.0+10721+14d8e0d5.src::python38:3.8, babel-2.7.0-11.module+el8.5.0+11015+9c1c7c42.src::python38:3.8 +47
    • Red Hat Enterprise Linux CRB (v. 8) pytest-4.6.6-3.module+el8.4.0+8888+89bc7e79.src::python38-devel:3.8, python-atomicwrites-1.3.0-8.module+el8.4.0+8888+89bc7e79.src::python38-devel:3.8, python-attrs-19.3.0-3.module+el8.4.0+8888+89bc7e79.src::python38-devel:3.8 +15
  • RHSA-2023:2764 Released 2023-05-16 · Red Hat rating Moderate
    python39:3.9 and python39-devel:3.9 security update
    • Red Hat Enterprise Linux AppStream (v. 8) PyYAML-5.4.1-1.module+el8.5.0+10613+59a13ec4.src::python39:3.9, mod_wsgi-4.7.1-5.module+el8.7.0+16654+645aad7f.src::python39:3.9, numpy-1.19.4-3.module+el8.5.0+12204+54860423.src::python39:3.9 +47
    • Red Hat Enterprise Linux CRB (v. 8) Cython-0.29.21-5.module+el8.4.0+9822+20bf1249.src::python39-devel:3.9, pybind11-2.7.1-1.module+el8.6.0+12838+640e6226.src::python39-devel:3.9, pytest-6.0.2-2.module+el8.4.0+9822+20bf1249.src::python39-devel:3.9 +33
  • RHSA-2023:0833 Released 2023-02-21 · Red Hat rating Moderate
    python3 security update
    • Red Hat Enterprise Linux AppStream (v. 8) platform-python-3.6.8-48.el8_7.1, platform-python-debug-3.6.8-48.el8_7.1, platform-python-devel-3.6.8-48.el8_7.1 +3
    • Red Hat Enterprise Linux BaseOS (v. 8) platform-python-3.6.8-48.el8_7.1, python3-3.6.8-48.el8_7.1, python3-libs-3.6.8-48.el8_7.1 +1
Show 2 more Red Hat advisories
  • RHSA-2022:8353 Released 2022-11-15 · Red Hat rating Moderate
    python3.9 security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder (v. 9) python3-3.9.14-1.el9, python3-debug-3.9.14-1.el9, python3-idle-3.9.14-1.el9 +2
    • Red Hat Enterprise Linux AppStream (v. 9) python-unversioned-command-3.9.14-1.el9, python3-devel-3.9.14-1.el9, python3-tkinter-3.9.14-1.el9
    • Red Hat Enterprise Linux BaseOS (v. 9) python3-3.9.14-1.el9, python3-libs-3.9.14-1.el9, python3.9-3.9.14-1.el9
  • RHSA-2022:6766 Released 2022-10-03 · Red Hat rating Moderate
    rh-python38-python security update
    • Red Hat Software Collections for RHEL Workstation(v. 7) rh-python38-python-3.8.14-1.el7, rh-python38-python-debug-3.8.14-1.el7, rh-python38-python-devel-3.8.14-1.el7 +6
    • Red Hat Software Collections for RHEL(v. 7) rh-python38-python-3.8.14-1.el7, rh-python38-python-debug-3.8.14-1.el7, rh-python38-python-devel-3.8.14-1.el7 +6

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat CodeReady Linux Builder (v. 9)Fixed RHSA-2022:8353
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2023:0833, RHSA-2023:2763, RHSA-2023:2764
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2022:8353
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2023:0833
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2022:8353
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2023:2763, RHSA-2023:2764
Red Hat Software Collections for RHEL Workstation(v. 7)Fixed RHSA-2022:6766
Red Hat Software Collections for RHEL(v. 7)Fixed RHSA-2022:6766
Not affected: 3 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-28861
  2. 2026-10-03 Alias added: GHSA-h7f6-hc46-frrv

References

Patch 2

Advisory 16

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences