CVE-2026-15308
published 2026-07-09CVE-2026-15308: The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing…
PriorityP339high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
0.55%
42.5th percentile
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| ansible-automation-platform | bootc-automation-portal-rhel9 | — | — |
| container-native-virtualization | ocp-virt-validation-checkup-rhel9 | — | — |
| debian | python3.11 | — | — |
| debian | python3.13 | — | — |
| debian | python3.14 | — | — |
| debian | python3.9 | — | — |
| exploit-intelligence-tech-preview | vulnerability-analysis-rhel9 | — | — |
| python | python | < 3.15.0 | 3.15.0 |
| python | python | — | — |
| python36_3.6 | python36 | — | — |
| python_software_foundation | cpython | < 3.15.0 | 3.15.0 |
| rhelai3 | bootc-aws-cuda-rhel9 | — | — |
| rhelai3 | bootc-azure-cuda-rhel9 | — | — |
| rhelai3 | bootc-azure-rocm-rhel9 | — | — |
| rhelai3 | bootc-cuda-rhel9 | — | — |
| rhelai3 | bootc-gaudi-rhel9 | — | — |
| rhelai3 | bootc-gcp-cuda-rhel9 | — | — |
| rhelai3 | bootc-rocm-rhel9 | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv4.08.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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_redhat8.7HIGH
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Red Hat
python: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations
vendor_redhat·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CWE-835 python: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations
python: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations
A flaw was found in Python. Its incremental HTML parser can be exploited by a remote attacker. By sending specially crafted, uncontrolled data with repeated, incomplete markup declarations, the attacker can cause the system to consume excessive central processing unit (CPU) resources. This leads to a denial of service, making the affected system unresponsive.
Statement: This Important vulnerability in Python's `html.parser.HTMLParser` can lead to a denial of service. By supplying specially crafted, malformed HTML with repeated unterminated markup declarations, an attacker can cause excessive CPU consumption, rendering the system unresponsive. Red Hat products utilizing this parser to proces
GHSA
The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.
ghsa_unreviewed·2026-07-09
CVE-2026-15308 [CRITICAL] CWE-400 The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-15308 python3.13: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.13: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 python3.13: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python3.9: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.9: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 python3.9: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python3.15: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.15: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 python3.15: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python3.10: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.10: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 python3.10: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python3.11: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.11: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 python3.11: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 asahi-installer: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 asahi-installer: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 asahi-installer: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python3.13: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [epel-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.13: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [epel-all]
CVE-2026-15308 python3.13: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [epel-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python3.6: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.6: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 python3.6: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python3.12: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.12: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 python3.12: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations
CVE-2026-15308 python: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 mingw-python3: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 mingw-python3: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 mingw-python3: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 python3.14: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 python3.14: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
CVE-2026-15308 python3.14: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
Bugzilla
CVE-2026-15308 asahi-installer: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [epel-all]
bugzilla·2026-07-09·CVSS 8.7
CVE-2026-15308 [HIGH] CVE-2026-15308 asahi-installer: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [epel-all]
CVE-2026-15308 asahi-installer: Python: CPU Denial of Service in HTML parser via repeated unterminated markup declarations [epel-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
The incremental HTML parser (html.parser.HTMLParser) allows for CPU
denial-of-service through repeated unterminated markup declarations when
processing uncontrolled data.
https://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9https://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969cedhttps://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606https://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bdhttps://github.com/python/cpython/issues/153030https://github.com/python/cpython/pull/153031https://mail.python.org/archives/list/[email protected]/thread/F6453LWKSHKCTWFLCOURWPLETNUIW2Z5/http://www.openwall.com/lists/oss-security/2026/07/09/4
2026-07-09
Published