Medium
HTMLParser quadratic complexity when processing malformed inputs
Type: advisorySources: OSV
The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs potentially leading to amplified denial-of-service.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2025-6069
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 03:13 UTC · Revision 1
Source evidence
HTMLParser quadratic complexity when processing malformed inputs
core-osv · Original sourcePublished 17 Jun 2025, 13:39 UTC
The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs potentially leading to amplified denial-of-service.
osv:CVE-2025-6069
Complete source record
{
"id": "7162433c1446168bcf57daf797b8c14535d73d5ce71e21286491bc3afc753132",
"url": "https://osv.dev/vulnerability/CVE-2025-6069",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "HTMLParser quadratic complexity when processing malformed inputs",
"summary": "The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs potentially leading to amplified denial-of-service.",
"evidence": "osv:CVE-2025-6069",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2025-6069",
"aliases": [
"BIT-libpython-2025-6069",
"BIT-python-2025-6069",
"BIT-python-min-2025-6069",
"CVE-2025-6069",
"PSF-2025-10"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/python/cpython",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "91bdb00dfed8634de52e2f64cba7545deb20f74c"
},
{
"introduced": "b494f5935c92951e75597bfe1c8b1f3112fec270"
},
{
"fixed": "f08d3c437bc5f41973ddd11f4cfc3d9fe04010f7"
},
{
"introduced": "deaf509e8fc6e0363bd6f26d52ad42f976ec42f2"
},
{
"fixed": "cd1c3a6342869b7346c1b5c27b8de9c6ef9c4e69"
},
{
"introduced": "0fb18b02c8ad56299d6a2910be0bab8ad601ef24"
},
{
"fixed": "4a5632fbf9bf59477c540e3f53fa7cdbeea3e3f5"
},
{
"introduced": "60403a5409ff2c3f3b07dd2ca91a7a3e096839c7"
},
{
"fixed": "4e665351082c50018fb31d80db25b4693057393e"
},
{
"introduced": "b092705907c758d4f9742028652c9802f9f03dd3"
},
{
"fixed": "26d485d12255a10a8e965b561e7d8a70a732ec69"
},
{
"fixed": "4455cbabf991e202185a25a631af206f60bbc949"
},
{
"fixed": "6eb6c5dbfb528bd07d77b60fd71fd05d81d45c41"
},
{
"fixed": "d851f8e258c7328814943e923a7df81bca15df4b"
},
{
"fixed": "8d1b3dfa09135affbbf27fb8babcf3c11415df49"
},
{
"fixed": "ab0893fd5c579d9cea30841680e6d35fc478afb5"
},
{
"fixed": "f3c6f882cddc8dc30320d2e73edf019e201394fc"
},
{
"fixed": "fdc9d214c01cb4588f540cfa03726bbf2a33fc15"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "3.9.24"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"introduced": "3.10.0"
},
{
"fixed": "3.10.19"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"introduced": "3.11.0"
},
{
"fixed": "3.11.14"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"introduced": "3.12.0"
},
{
"fixed": "3.12.12"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"introduced": "3.13.0"
},
{
"fixed": "3.13.6"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"introduced": "3.14.0a1"
},
{
"fixed": "3.14.0b3"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"fixed": "4455cbabf991e202185a25a631af206f60bbc949"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "6eb6c5dbfb528bd07d77b60fd71fd05d81d45c41"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "d851f8e258c7328814943e923a7df81bca15df4b"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "8d1b3dfa09135affbbf27fb8babcf3c11415df49"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "ab0893fd5c579d9cea30841680e6d35fc478afb5"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "f3c6f882cddc8dc30320d2e73edf019e201394fc"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "fdc9d214c01cb4588f540cfa03726bbf2a33fc15"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"v3.13.5",
"v3.13.4",
"v3.11.13",
"v3.9.23",
"v3.10.18",
"v3.12.11",
"v3.14.0b2",
"v3.14.0b1",
"v3.9.22",
"v3.13.3",
"v3.11.12",
"v3.12.10",
"v3.10.17",
"v3.13.2",
"v3.12.9",
"v3.13.1",
"v3.12.8",
"v3.10.16",
"v3.11.11",
"v3.9.21",
"v3.13.0",
"v3.12.7",
"v3.11.10",
"v3.10.15",
"v3.12.6",
"v3.9.20",
"v3.12.5",
"v3.12.4",
"v3.12.3",
"v3.11.9",
"v3.10.14",
"v3.9.19",
"v3.12.2",
"v3.11.8",
"v3.12.1",
"v3.11.7",
"v3.11.6",
"v3.12.0",
"v3.11.5",
"v3.9.18",
"v3.10.13",
"v3.11.4",
"v3.10.12",
"v3.9.17",
"v3.10.11",
"v3.11.3",
"v3.10.10",
"v3.11.2",
"v3.10.9",
"v3.11.1",
"v3.9.16",
"v3.11.0rc2",
"v3.10.8",
"v3.9.15",
"v3.9.14",
"v3.10.7",
"v3.11.0rc1",
"v3.10.6",
"v3.11.0b5",
"v3.11.0b4",
"v3.10.5",
"v3.11.0b3",
"v3.11.0b2",
"v3.9.13",
"v3.11.0b1",
"v3.11.0a7",
"v3.10.4",
"v3.9.12",
"v3.9.11",
"v3.10.3",
"v3.11.0a6",
"v3.11.0a5",
"v3.11.0a4",
"v3.10.2",
"v3.11.0a3",
"v3.10.1",
"v3.9.9",
"v3.9.8",
"v3.10.0rc2",
"v3.9.7",
"v3.10.0rc1",
"v3.10.0b4",
"v3.9.6",
"v3.10.0b3",
"v3.10.0b2",
"v3.10.0b1",
"v3.9.5",
"v3.10.0a7",
"v3.9.2",
"v3.9.2rc1",
"v3.10.0a1",
"v3.9.0b5",
"v3.9.0b3",
"v3.9.0b1",
"v3.9.0a2",
"v3.7.0a2",
"v3.6.0b1",
"v3.6.0a3",
"v3.5.0b1",
"v3.5.0a4",
"v3.5.0a3",
"v3.5.0a2",
"v3.5.0a1",
"v3.4.0b3",
"v3.4.0b2",
"v3.4.0b1",
"v3.4.0a4",
"v3.4.0a3",
"v3.4.0a2",
"v3.4.0a1",
"v3.3.0rc3",
"v3.3.0rc2",
"v3.3.0rc1",
"v3.3.0b2",
"v3.3.0b1",
"v3.3.0a4",
"v3.3.0a3",
"v3.3.0a2",
"v3.2rc3",
"v3.2rc2",
"v3.2rc1",
"v3.2b2",
"v3.2b1",
"v3.2a4",
"v3.2a3",
"v3.2a2",
"v3.2a1",
"v3.1",
"v3.1rc2",
"v3.1rc1",
"v3.1b1",
"v3.1a2",
"v3.1a1",
"v3.0rc3",
"v3.0rc2",
"v3.0rc1",
"v3.0b3",
"v3.0b2",
"v3.0b1",
"v3.0a5",
"v3.0a4",
"v3.0a3",
"v3.0a2",
"v3.0a1",
"v2.4",
"v2.4c1",
"v2.4b2",
"v2.4b1",
"v2.4a3",
"v2.4a2",
"v2.4a1",
"v2.3c2",
"v2.3c1",
"v2.2a3",
"v2.1",
"v2.1c2",
"v2.1c1",
"v2.1b2",
"v2.1b1",
"v2.1a2",
"v2.1a1",
"v2.0",
"v2.0c1",
"v2.0b2",
"v2.0b1",
"v1.6a2",
"v1.6a1",
"v1.5.2",
"v1.5.2c1",
"v1.5.2b2",
"v1.5.2b1",
"v1.5.2a2",
"v1.5.2a1",
"v1.5.1",
"v1.5",
"v1.5b2",
"v1.5b1",
"v1.5a4",
"v1.5a3",
"v1.5a2",
"v1.5a1",
"v1.4",
"v1.4b3",
"v1.4b2",
"v1.4b1",
"v1.3",
"v1.3b1",
"v1.2",
"v1.2b4",
"v1.2b3",
"v1.2b2",
"v1.2b1",
"v1.1.1",
"v1.1",
"v1.0.2",
"v1.0.1",
"v0.9.9",
"v0.9.8"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-6069.json"
}
}
],
"modified": "2026-10-28T02:30:32.811557682Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/6xxx/CVE-2025-6069.json",
"https://mail.python.org/archives/list/security-announce@python.org/thread/K5PIYLR6EP3WR7ZOKKYQUWEDNQVUXOYM/",
"https://nvd.nist.gov/vuln/detail/CVE-2025-6069",
"https://github.com/python/cpython/issues/135462",
"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/pull/135464",
"https://github.com/python/cpython"
],
"provider_metadata": {
"cwe_ids": [
"CWE-1333"
],
"cna_assigner": "PSF",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/6xxx/CVE-2025-6069.json"
}
},
"related_cves": [
{
"value": "CVE-2025-6069",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 499962,
"published_at": "2025-06-17T13:39:46.058+00:00"
}