HTTP client can get stuck infinitely reading len(line) < 64k lines after receiving a '100 Continue' HTTP response. This could lead to the client being a bandwidth sink for anyone in control of a server. References: https://bugs.python.org/issue44022 https://github.com/python/cpython/pull/25916 https://github.com/python/cpython/pull/26503 https://build.opensuse.org/package/view_file/devel:languages:python:Factory/python/bpo44022-fix-http-client-infinite-line-reading-after-a-HTTP-100-Continue.patch?expand=1 https://bugzilla.redhat.com/show_bug.cgi?id=1991918
Setting CVSS score to 6.5/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H . User Interaction (UI) set to Required (R) because the flaw is in the HTTP client code, thus the attack scenario that was considered is that of a user running a python script/tool to erroneously connect to a malicious HTTP server. Libraries or tools that do not require user interaction are assumed to connect to trusted servers which would need to be compromised by an attacker first in order to trigger this vulnerability. In this last case, you'd have UI=N, but AC=H giving a CVSSv3.1 score of 5.9 that is lower than the current 6.5. For this reason we chose to evaluate the worst-case reasonable scenario. Given the flaw is in the client side and it requires automatically connecting to a compromised but trusted server or manually connecting to a malicious server, the Impact of this flaw has been set to Low. It requires indeed unlikely circumstances to be able to be exploited and when it is it is enough to stop the client or restart it.
Created mingw-python3 tracking bugs for this issue: Affects: fedora-all [bug 1997670] Created python2.7 tracking bugs for this issue: Affects: fedora-all [bug 1997671] Created python3.10 tracking bugs for this issue: Affects: fedora-all [bug 1997672] Created python3.5 tracking bugs for this issue: Affects: fedora-all [bug 1997673] Created python3.6 tracking bugs for this issue: Affects: fedora-all [bug 1997674] Created python3.7 tracking bugs for this issue: Affects: fedora-all [bug 1997675] Created python3.8 tracking bugs for this issue: Affects: fedora-all [bug 1997676] Created python3.9 tracking bugs for this issue: Affects: fedora-all [bug 1997677] Created python34 tracking bugs for this issue: Affects: epel-all [bug 1997669]
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2021:4160 https://access.redhat.com/errata/RHSA-2021:4160
This issue has been addressed in the following products: Red Hat Software Collections for Red Hat Enterprise Linux 7 Via RHSA-2022:1663 https://access.redhat.com/errata/RHSA-2022:1663
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2022:1764 https://access.redhat.com/errata/RHSA-2022:1764
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2022:1821 https://access.redhat.com/errata/RHSA-2022:1821
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2022:1986 https://access.redhat.com/errata/RHSA-2022:1986
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2021-3737