{"id":"CVE-2026-9769","state":"PUBLISHED","title":"justhtml before 1.10.0 Denial of Service via deeply nested HTML","description":"justhtml through 1.9.1 (fixed in 1.10.0) is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML() construction, TreeBuilder.finish() unconditionally calls _populate_selectedcontent(), which recursively traverses the DOM tree via _find_elements()/_find_element() without a depth bound. An attacker who can supply HTML for parsing can provide deeply nested elements (e.g., ~1000 nested <div> tags, roughly 11 KB) to exceed CPython's default recursion limit and trigger an unhandled RecursionError, which may abort parsing, fail requests, or terminate a worker/process depending on the host application's exception handling.","publishedAt":"2026-08-23T13:34:15.503Z","updatedAt":"2026-08-24T17:54:01.074Z","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":"VulnCheck"},"assigner":"VulnCheck","products":["EmilStenstrom justhtml"],"affected":[{"vendor":"EmilStenstrom","product":"justhtml","packageURL":"pkg:pypi/justhtml","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.10.0","versionType":"semver"},{"version":"1.10.0","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-v7cf-c9rm-wm3j","https://www.vulncheck.com/advisories/justhtml-before-denial-of-service-via-deeply-nested-html"],"weaknesses":["CWE-674"],"ingestedAt":"2026-10-29T20:13:52.441Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/9xxx/CVE-2026-9769.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-9769","state":"PUBLISHED","datePublished":"2026-08-23T13:34:15.503Z","dateUpdated":"2026-08-24T17:54:01.074Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-05-27T20:38:38.588Z"},"containers":{"cna":{"title":"justhtml before 1.10.0 Denial of Service via deeply nested HTML","descriptions":[{"lang":"en","value":"justhtml through 1.9.1 (fixed in 1.10.0) is vulnerable to uncontrolled recursion leading to denial of service. During JustHTML() construction, TreeBuilder.finish() unconditionally calls _populate_selectedcontent(), which recursively traverses the DOM tree via _find_elements()/_find_element() without a depth bound. An attacker who can supply HTML for parsing can provide deeply nested elements (e.g., ~1000 nested <div> tags, roughly 11 KB) to exceed CPython's default recursion limit and trigger an unhandled RecursionError, which may abort parsing, fail requests, or terminate a worker/process depending on the host application's exception handling."}],"affected":[{"vendor":"EmilStenstrom","product":"justhtml","packageURL":"pkg:pypi/justhtml","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.10.0","versionType":"semver"},{"version":"1.10.0","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-v7cf-c9rm-wm3j","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-v7cf-c9rm-wm3j)"},{"url":"https://www.vulncheck.com/advisories/justhtml-before-denial-of-service-via-deeply-nested-html","name":"VulnCheck Advisory: justhtml before 1.10.0 Denial of Service via deeply nested HTML","tags":["third-party-advisory"]}],"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"},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-674","lang":"en","description":"Uncontrolled Recursion","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-08-23T13:34:15.503Z"},"datePublic":"2026-03-15T00:00:00.000Z","credits":[{"lang":"en","value":"kq5y","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-v7cf-c9rm-wm3j","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-24T17:53:32.041480Z","id":"CVE-2026-9769","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-24T17:54:01.074Z"}}]}}}