{"cve":"CVE-2021-43818","nvd":{"published":"2021-12-13T18:15:08.387","modified":"2026-06-17T04:11:30.140","status":"Modified","description":"lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L","score":7.1},"cwes":["CWE-79","CWE-74"],"references":["https://github.com/lxml/lxml/commit/12fa9669007180a7bb87d990c375cf91ca5b664a","https://github.com/lxml/lxml/commit/a3eacbc0dcf1de1c822ec29fb7d090a4b1712a9c#diff-59130575b4fb2932c957db2922977d7d89afb0b2085357db1a14615a2fcad776","https://github.com/lxml/lxml/commit/f2330237440df7e8f39c3ad1b1aa8852be3b27c0","https://github.com/lxml/lxml/security/advisories/GHSA-55x5-fj6c-h6m8","https://lists.debian.org/debian-lts-announce/2021/12/msg00037.html"],"products":["debian:debian_linux","fedoraproject:fedora","lxml:lxml","netapp:hci_storage_node_firmware","netapp:solidfire","netapp:solidfire_enterprise_sds","oracle:communications_cloud_native_core_binding_support_function","oracle:communications_cloud_native_core_network_exposure_function","oracle:communications_cloud_native_core_policy","oracle:http_server","oracle:zfs_storage_appliance_kit"],"source":"nvd","synced_at":"2026-10-19T21:25:41.256909649+00:00"},"epss":{"cve":"CVE-2021-43818","score":0.02663,"percentile":0.85712,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-55x5-fj6c-h6m8","url":"https://osv.dev/vulnerability/GHSA-55x5-fj6c-h6m8","summary":"lxml's HTML Cleaner allows crafted and SVG embedded scripts to pass through","modified":"2026-07-08T06:28:08.789724998Z","packages":[{"ecosystem":"PyPI","name":"lxml","purl":"pkg:pypi/lxml","ranges":["<4.6.5"],"fixed":["4.6.5"]}]},{"id":"PYSEC-2021-852","url":"https://osv.dev/vulnerability/PYSEC-2021-852","summary":"","modified":"2026-04-09T18:24:01.261452Z","packages":[{"ecosystem":"PyPI","name":"lxml","purl":"pkg:pypi/lxml","ranges":["<4.6.5"],"fixed":["4.6.5"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}