The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs potentially leading to amplified denial-of-service.
Weakness
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Red Hat Enterprise Linux 8 | RedHat | python39:3.9-8100020251126112422.d47b87a4 | * |
| Red Hat Enterprise Linux 8 | RedHat | python39-devel:3.9-8100020251126112422.d47b87a4 | * |
| Red Hat Enterprise Linux 9 | RedHat | python3.9-0:3.9.25-2.el9_7 | * |
| Red Hat Enterprise Linux 9 | RedHat | python3.9-0:3.9.25-2.el9_7 | * |
| Red Hat Ceph Storage 7 | RedHat | rhceph/rhceph-7-rhel9:sha256:7593f0bc7a6b312b5b686f0077443f11e9952128801809828e8bd3a73314c116 | * |
| Red Hat Ceph Storage 8 | RedHat | rhceph/rhceph-8-rhel9:sha256:c1c3e3e46bb57c2c99378b7336aa2c2015b7279dcb3df7fdccc8c3dee1522ba6 | * |
| Red Hat Discovery 2 | RedHat | discovery/discovery-server-rhel9:sha256:75723049a444b5136e2d40920e2852f0840fecf60832a8bbb06e488fc9bba543 | * |
| Red Hat Discovery 2 | RedHat | discovery/discovery-ui-rhel9:sha256:899bd7f941512d54af8ab369ca03028a7d27d05887ccce24bc12c7ccd3e4dbee | * |
| Red Hat Update Infrastructure 5 | RedHat | rhui5/cds-rhel9:sha256:87d268fd03fa0063620a043b43bce078144e06849ca6b83fd0e375c13ecb15be | * |
| Red Hat Update Infrastructure 5 | RedHat | rhui5/haproxy-rhel9:sha256:c0cb48d44556c064626eab0d70e5f427ac132bbd921342dcb862267413bf8d16 | * |
| Red Hat Update Infrastructure 5 | RedHat | rhui5/installer-rhel9:sha256:e1d64fbd0e4b90259d9fbb94736ed74c7c384d13067c6bbbb107c664683cb1a9 | * |
| Red Hat Update Infrastructure 5 | RedHat | rhui5/rhua-rhel9:sha256:4642951a6a57511f8b481a6481fcd417fc7f3de86511cdab28b9b89639c2bdb2 | * |
| Jython | Ubuntu | oracular | * |
| Jython | Ubuntu | plucky | * |
| Python2.7 | Ubuntu | bionic | * |
| Python2.7 | Ubuntu | esm-apps/focal | * |
| Python2.7 | Ubuntu | esm-apps/jammy | * |
| Python2.7 | Ubuntu | esm-infra-legacy/trusty | * |
| Python2.7 | Ubuntu | esm-infra/bionic | * |
| Python2.7 | Ubuntu | esm-infra/xenial | * |
| Python2.7 | Ubuntu | focal | * |
| Python2.7 | Ubuntu | jammy | * |
| Python2.7 | Ubuntu | trusty | * |
| Python2.7 | Ubuntu | trusty/esm | * |
| Python2.7 | Ubuntu | xenial | * |
| Python3.10 | Ubuntu | jammy | * |
| Python3.11 | Ubuntu | esm-apps/jammy | * |
| Python3.11 | Ubuntu | jammy | * |
| Python3.12 | Ubuntu | noble | * |
| Python3.12 | Ubuntu | oracular | * |
| Python3.13 | Ubuntu | devel | * |
| Python3.13 | Ubuntu | oracular | * |
| Python3.13 | Ubuntu | plucky | * |
| Python3.13 | Ubuntu | questing | * |
| Python3.13 | Ubuntu | upstream | * |
| Python3.14 | Ubuntu | upstream | * |
| Python3.4 | Ubuntu | esm-infra-legacy/trusty | * |
| Python3.4 | Ubuntu | trusty | * |
| Python3.4 | Ubuntu | trusty/esm | * |
| Python3.5 | Ubuntu | esm-infra-legacy/trusty | * |
| Python3.5 | Ubuntu | esm-infra/xenial | * |
| Python3.5 | Ubuntu | trusty | * |
| Python3.5 | Ubuntu | trusty/esm | * |
| Python3.5 | Ubuntu | xenial | * |
| Python3.6 | Ubuntu | bionic | * |
| Python3.6 | Ubuntu | esm-infra/bionic | * |
| Python3.7 | Ubuntu | bionic | * |
| Python3.7 | Ubuntu | esm-apps/bionic | * |
| Python3.8 | Ubuntu | bionic | * |
| Python3.8 | Ubuntu | esm-apps/bionic | * |
| Python3.8 | Ubuntu | esm-infra/focal | * |
| Python3.8 | Ubuntu | focal | * |
| Python3.9 | Ubuntu | esm-apps/focal | * |
| Python3.9 | Ubuntu | focal | * |
Extended Description
Attackers can create crafted inputs that
intentionally cause the regular expression to use
excessive backtracking in a way that causes the CPU
consumption to spike.
Potential Mitigations
Related Attack Patterns
References
- https://github.com/python/cpython/commit/4455cbabf991e202185a25a631af206f60bbc949
- https://github.com/python/cpython/commit/6eb6c5dbfb528bd07d77b60fd71fd05d81d45c41
- https://github.com/python/cpython/commit/8d1b3dfa09135affbbf27fb8babcf3c11415df49
- https://github.com/python/cpython/commit/ab0893fd5c579d9cea30841680e6d35fc478afb5
- https://github.com/python/cpython/commit/d851f8e258c7328814943e923a7df81bca15df4b
- https://github.com/python/cpython/commit/f3c6f882cddc8dc30320d2e73edf019e201394fc
- https://github.com/python/cpython/commit/fdc9d214c01cb4588f540cfa03726bbf2a33fc15
- https://github.com/python/cpython/issues/135462
- https://github.com/python/cpython/pull/135464
- https://mail.python.org/archives/list/security-announce@python.org/thread/K5PIYLR6EP3WR7ZOKKYQUWEDNQVUXOYM/