{"id":"CVE-2026-15308","state":"PUBLISHED","title":"Incremental HTMLParser feed() allows CPU-exhaustion DoS via repeated unterminated markup declarations","description":"The incremental HTML parser (html.parser.HTMLParser) allows for CPU\ndenial-of-service through repeated unterminated markup declarations when\nprocessing uncontrolled data.","publishedAt":"2026-07-09T17:10:57.317Z","updatedAt":"2026-08-13T00:28:26.690Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","source":"PSF"},"assigner":"PSF","products":["Python Software Foundation CPython"],"affected":[{"vendor":"Python Software Foundation","product":"CPython","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"3.10.21","versionType":"python"},{"version":"3.11.0","status":"affected","lessThan":"3.11.16","versionType":"python"},{"version":"3.12.0","status":"affected","lessThan":"3.12.14","versionType":"python"},{"version":"3.13.0","status":"affected","lessThan":"3.13.15","versionType":"python"},{"version":"3.14.0","status":"affected","lessThan":"3.14.7","versionType":"python"},{"version":"3.15.0a1","status":"affected","lessThan":"3.15.0b4","versionType":"python"}],"modules":["html.parser","html"],"repo":"https://github.com/python/cpython"}],"references":["https://mail.python.org/archives/list/security-announce@python.org/thread/F6453LWKSHKCTWFLCOURWPLETNUIW2Z5/","https://github.com/python/cpython/pull/153031","https://github.com/python/cpython/issues/153030","https://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9","https://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969ced","https://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606","https://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bd","https://github.com/python/cpython/commit/785df8f743800661961528970f8598edcd291c14","https://github.com/python/cpython/commit/1e7956f1a722df9aabc509c30f8fbdc3a2b4fdc7","https://github.com/python/cpython/commit/c2390b9376e35a701ed3acc597b8fc87546c9b00","http://www.openwall.com/lists/oss-security/2026/07/09/4"],"weaknesses":["CWE-400"],"ingestedAt":"2026-10-29T20:11:00.674Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/15xxx/CVE-2026-15308.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-15308","state":"PUBLISHED","datePublished":"2026-07-09T17:10:57.317Z","dateUpdated":"2026-08-13T00:28:26.690Z","assignerShortName":"PSF","assignerOrgId":"28c92f92-d60d-412d-b760-e73465c3df22","dateReserved":"2026-07-09T17:04:11.926Z"},"containers":{"cna":{"title":"Incremental HTMLParser feed() allows CPU-exhaustion DoS via repeated unterminated markup declarations","descriptions":[{"lang":"en","value":"The incremental HTML parser (html.parser.HTMLParser) allows for CPU\ndenial-of-service through repeated unterminated markup declarations when\nprocessing uncontrolled data."}],"affected":[{"vendor":"Python Software Foundation","product":"CPython","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"3.10.21","versionType":"python"},{"version":"3.11.0","status":"affected","lessThan":"3.11.16","versionType":"python"},{"version":"3.12.0","status":"affected","lessThan":"3.12.14","versionType":"python"},{"version":"3.13.0","status":"affected","lessThan":"3.13.15","versionType":"python"},{"version":"3.14.0","status":"affected","lessThan":"3.14.7","versionType":"python"},{"version":"3.15.0a1","status":"affected","lessThan":"3.15.0b4","versionType":"python"}],"modules":["html.parser","html"],"repo":"https://github.com/python/cpython"}],"references":[{"url":"https://mail.python.org/archives/list/security-announce@python.org/thread/F6453LWKSHKCTWFLCOURWPLETNUIW2Z5/","tags":["vendor-advisory"]},{"url":"https://github.com/python/cpython/pull/153031","tags":["patch"]},{"url":"https://github.com/python/cpython/issues/153030","tags":["issue-tracking"]},{"url":"https://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9","tags":["patch"]},{"url":"https://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969ced","tags":["patch"]},{"url":"https://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606","tags":["patch"]},{"url":"https://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bd","tags":["patch"]},{"url":"https://github.com/python/cpython/commit/785df8f743800661961528970f8598edcd291c14","tags":["patch"]},{"url":"https://github.com/python/cpython/commit/1e7956f1a722df9aabc509c30f8fbdc3a2b4fdc7","tags":["patch"]},{"url":"https://github.com/python/cpython/commit/c2390b9376e35a701ed3acc597b8fc87546c9b00","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.7,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","description":"CWE-400","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"PSF","orgId":"28c92f92-d60d-412d-b760-e73465c3df22","dateUpdated":"2026-08-13T00:28:26.690Z"},"credits":[{"lang":"en","type":"reporter","value":"Edward-x (https://github.com/YLChen-007)"},{"lang":"en","type":"remediation developer","value":"Serhiy Storchaka (https://github.com/serhiy-storchaka)"},{"lang":"en","type":"remediation reviewer","value":"Gregory P. Smith (https://github.com/gpshead)"},{"lang":"en","type":"coordinator","value":"Seth Larson (https://github.com/sethmlarson)"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-09T17:31:19.781935Z","id":"CVE-2026-15308","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-09T17:31:27.360Z"}},{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/07/09/4"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-07-09T19:32:36.790Z"}}]}}}