{"answers":{"affected":"3 open source packages ship an affected version, including lxml. It affects 5 products.","exploited":"There is no known exploitation of CVE-2021-28957 in the wild and no public exploit code.","fix":"Upgrade lxml to 4.6.3 or later.","what":"CVE-2021-28957 is a medium-severity cross-site scripting vulnerability in Debian Debian Linux, published on 21 Mar 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2021-28957 and fix it if it is affected.\n\nWhat it is: CVE-2021-28957 is a medium-severity cross-site scripting vulnerability in Debian Debian Linux, published on 21 Mar 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2021-28957 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- lxml (PyPI): affected all versions; fixed in 4.6.3\n- lxml (PyPI): affected all versions; fixed in 4.6.3\n- lxml (PyPI): affected all versions; fixed in 4.6.3\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-28957/ (Markdown: https://insights.sbomify.com/CVE-2021-28957/index.md)","id":"CVE-2021-28957","markdown":"https://insights.sbomify.com/CVE-2021-28957/index.md","name":"CVE-2021-28957","record":{"aliases":["ALPINE-CVE-2021-28957","ALSA-2021:4158","AZL-6808","DEBIAN-CVE-2021-28957","DLA-2606-1","DSA-4880-1","GHSA-jq4v-f5q6-mjqq","MGASA-2021-0246","OESA-2021-1178","PYSEC-2021-19","RHSA-2021:4158","RLSA-2021:4158","SUSE-SU-2022:3934-1","SUSE-SU-2022:3937-1","UBUNTU-CVE-2021-28957","USN-4896-1","USN-4896-2","openSUSE-SU-2024:11473-1","openSUSE-SU-2025:14647-1"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"yes","non_default_config":true,"product_category":"Python lxml library","requires_auth":"none","summary":"Remote attackers can execute arbitrary JavaScript via XSS in python-lxml when specific sanitizer options are disabled, affecting applications using the library.","user_interaction":"required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mitre","cpe":[{"product":"debian_linux","vendor":"debian"},{"product":"fedora","vendor":"fedoraproject"},{"product":"lxml","vendor":"lxml"},{"product":"snapcenter","vendor":"netapp"},{"product":"zfs_storage_appliance_kit","vendor":"oracle"}],"cvss":{"score":6.1,"severity":"medium","source":"cisa-adp","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"description":"An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.","ecosystems":["AlmaLinux:8","PyPI","Red Hat:enterprise_linux:8::appstream","Rocky Linux:8","SUSE:Linux Enterprise Module for Public Cloud 12","SUSE:Linux Enterprise Server 12 SP5","SUSE:Linux Enterprise Server for SAP Applications 12 SP5","openSUSE:Tumbleweed"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"lxml vulnerable to Cross-Site Scripting","id":"CVE-2021-28957","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":"debian:debian_linux","products":["debian:debian_linux","fedoraproject:fedora","netapp:snapcenter","oracle:zfs_storage_appliance_kit"],"type":"xss","year":"2021"},"n_packages":14,"n_references":10,"next":{"headline":"Command injection in n/a","id":"CVE-2021-28958"},"packages":[{"ecosystem":"PyPI","fixed":["4.6.3"],"introduced":["0"],"last_affected":[],"package":"lxml","purl":null,"source":"GHSA-jq4v-f5q6-mjqq"},{"ecosystem":"PyPI","fixed":["4.6.3"],"introduced":["0"],"last_affected":[],"package":"lxml","purl":"pkg:pypi/lxml","source":"GHSA-jq4v-f5q6-mjqq"},{"ecosystem":"PyPI","fixed":["4.6.3"],"introduced":["0"],"last_affected":[],"package":"lxml","purl":"pkg:pypi/lxml","source":"PYSEC-2021-19"},{"ecosystem":"AlmaLinux:8","fixed":["4.2.3-3.el8"],"introduced":["0"],"last_affected":[],"package":"python3-lxml","purl":"pkg:rpm/almalinux/python3-lxml","source":"ALSA-2021:4158"},{"ecosystem":"Red Hat:enterprise_linux:8::appstream","fixed":["0:4.2.3-3.el8"],"introduced":["0"],"last_affected":[],"package":"python-lxml","purl":"pkg:rpm/redhat/python-lxml","source":"RHSA-2021:4158"},{"ecosystem":"Red Hat:enterprise_linux:8::appstream","fixed":["0:4.2.3-3.el8"],"introduced":["0"],"last_affected":[],"package":"python-lxml-debugsource","purl":"pkg:rpm/redhat/python-lxml-debugsource","source":"RHSA-2021:4158"},{"ecosystem":"Red Hat:enterprise_linux:8::appstream","fixed":["0:4.2.3-3.el8"],"introduced":["0"],"last_affected":[],"package":"python3-lxml","purl":"pkg:rpm/redhat/python3-lxml","source":"RHSA-2021:4158"},{"ecosystem":"Red Hat:enterprise_linux:8::appstream","fixed":["0:4.2.3-3.el8"],"introduced":["0"],"last_affected":[],"package":"python3-lxml-debuginfo","purl":"pkg:rpm/redhat/python3-lxml-debuginfo","source":"RHSA-2021:4158"},{"ecosystem":"Rocky Linux:8","fixed":["0:4.2.3-3.el8"],"introduced":["0"],"last_affected":[],"package":"python-lxml","purl":"pkg:rpm/rocky-linux/python-lxml?distro=rocky-linux-8-5-legacy\u0026epoch=0","source":"RLSA-2021:4158"},{"ecosystem":"SUSE:Linux Enterprise Module for Public Cloud 12","fixed":["3.3.5-3.15.1"],"introduced":["0"],"last_affected":[],"package":"python3-lxml","purl":"pkg:rpm/suse/python3-lxml\u0026distro=SUSE%20Linux%20Enterprise%20Module%20for%20Public%20Cloud%2012","source":"SUSE-SU-2022:3934-1"},{"ecosystem":"SUSE:Linux Enterprise Server 12 SP5","fixed":["3.6.1-3.6.1"],"introduced":["0"],"last_affected":[],"package":"python3-lxml","purl":"pkg:rpm/suse/python3-lxml\u0026distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5","source":"SUSE-SU-2022:3937-1"},{"ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 12 SP5","fixed":["3.6.1-3.6.1"],"introduced":["0"],"last_affected":[],"package":"python3-lxml","purl":"pkg:rpm/suse/python3-lxml\u0026distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5","source":"SUSE-SU-2022:3937-1"},{"ecosystem":"openSUSE:Tumbleweed","fixed":["3.14.5-1.1"],"introduced":["0"],"last_affected":[],"package":"translate-toolkit","purl":"pkg:rpm/opensuse/translate-toolkit\u0026distro=openSUSE%20Tumbleweed","source":"openSUSE-SU-2025:14647-1"},{"ecosystem":"openSUSE:Tumbleweed","fixed":["3.3.6-1.3"],"introduced":["0"],"last_affected":[],"package":"translate-toolkit","purl":"pkg:rpm/opensuse/translate-toolkit\u0026distro=openSUSE%20Tumbleweed","source":"openSUSE-SU-2024:11473-1"}],"prev":{"headline":"Code injection in n/a","id":"CVE-2021-28956"},"products":["n/a"],"published":"2021-03-21","related":[{"cvss_score":10,"headline":"ProFTPD Improper Access Control","id":"CVE-2015-3306","kev_date_added":"2026-10-08","published":"2015-05-18"},{"cvss_score":9.9,"headline":"RoundCube Webmail Deserialization of Untrusted Data","id":"CVE-2025-49113","kev_date_added":"2026-02-20","published":"2025-06-02"},{"cvss_score":9.8,"headline":"GNU InetUtils Argument Injection","id":"CVE-2026-24061","kev_date_added":"2026-01-26","published":"2026-01-21"},{"cvss_score":9.8,"headline":"Linux Kernel Improper Check for Unusual or Exceptional Conditions","id":"CVE-2025-39682","kev_date_added":"2026-09-18","published":"2025-09-05"},{"cvss_score":9.8,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2024-9680","kev_date_added":"2024-10-15","published":"2024-10-09"},{"cvss_score":9.8,"headline":"RARLAB UnRAR Directory Traversal","id":"CVE-2022-30333","kev_date_added":"2022-08-09","published":"2022-05-09"},{"cvss_score":9.8,"headline":"Roundcube Webmail SQL Injection","id":"CVE-2021-44026","kev_date_added":"2023-06-22","published":"2021-11-19"}],"sources":[{"class":"attribution","licence":"MIT","name":"AlmaLinux","prefix":"ALSA"},{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"class":"attribution","licence":"CC BY 4.0","name":"Red Hat","prefix":"RHSA"},{"class":"attribution","licence":"BSD","name":"Rocky Linux","prefix":"RLSA"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"SUSE"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"openSUSE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2025-12-17","vendors":["n/a"]},"summary":"Remote attackers can execute arbitrary JavaScript via XSS in python-lxml when specific sanitizer options are disabled, affecting applications using the library.","url":"https://insights.sbomify.com/CVE-2021-28957/"}