{"answers":{"affected":"3 open source packages ship an affected version, including nicegui. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21873 exists.","fix":"Upgrade nicegui to 3.5.0 or later.","what":"CVE-2026-21873 is a high-severity cross-site scripting vulnerability in zauberzeug nicegui, published on 8 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-21873 and fix it if it is affected.\n\nWhat it is: CVE-2026-21873 is a high-severity cross-site scripting vulnerability in zauberzeug nicegui, published on 8 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21873 exists.\n\nAffected packages and fixed versions:\n- nicegui (PyPI): affected from 2.22.0; fixed in 3.5.0\n- nicegui (PyPI): affected from 2.22.0; fixed in 3.5.0\n- nicegui (PyPI): affected from 2.22.0; fixed in 3.5.0\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-2026-21873/ (Markdown: https://insights.sbomify.com/CVE-2026-21873/index.md)","id":"CVE-2026-21873","markdown":"https://insights.sbomify.com/CVE-2026-21873/index.md","name":"CVE-2026-21873","record":{"aliases":["GHSA-mhpg-c27v-6mxr","PYSEC-2026-1702"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"Python UI framework","requires_auth":"none","summary":"Attackers can execute arbitrary JavaScript in NiceGUI applications via cross-site iframe manipulation of URL fragments.","user_interaction":"not_required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"nicegui","vendor":"zauberzeug"}],"cvss":{"score":7.2,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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":"NiceGUI is a Python-based UI framework. From versions 2.22.0 to 3.4.1, an unsafe implementation in the pushstate event listener used by ui.sub_pages allows an attacker to manipulate the fragment identifier of the URL, which they can do despite being cross-site, using an iframe. This issue has been patched in version 3.5.0.","ecosystems":["PyPI"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Zero-click XSS in all NiceGUI apps which uses `ui.sub_pages`","id":"CVE-2026-21873","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"xss","year":"2026"},"n_packages":3,"n_references":2,"next":{"headline":"NiceGUI has Redis connection leak via tab storage causes service degradation","id":"CVE-2026-21874"},"packages":[{"ecosystem":"PyPI","fixed":["3.5.0"],"introduced":["2.22.0"],"last_affected":[],"package":"nicegui","purl":null,"source":"GHSA-mhpg-c27v-6mxr"},{"ecosystem":"PyPI","fixed":["3.5.0"],"introduced":["2.22.0"],"last_affected":[],"package":"nicegui","purl":"pkg:pypi/nicegui","source":"GHSA-mhpg-c27v-6mxr"},{"ecosystem":"PyPI","fixed":["3.5.0"],"introduced":["2.22.0"],"last_affected":[],"package":"nicegui","purl":"pkg:pypi/nicegui","source":"PYSEC-2026-1702"}],"prev":{"headline":"NiceGUI apps are vulnerable to XSS which uses `ui.sub_pages` and render arbitrary user-provided links","id":"CVE-2026-21872"},"products":["nicegui"],"published":"2026-01-08","related":[{"cvss_score":7.5,"headline":"NiceGUI's Path Traversal via Unsanitized FileUpload.name Enables Arbitrary File Write","id":"CVE-2026-25732","kev_date_added":null,"published":"2026-02-06"},{"cvss_score":7.5,"headline":"NiceGUI Path Traversal Vulnerability in app.add_media_files() Allows Arbitrary File Reading","id":"CVE-2025-66645","kev_date_added":null,"published":"2025-12-09"},{"cvss_score":6.9,"headline":"NiceGUI's unvalidated chunk size parameter in media routes can cause memory exhaustion","id":"CVE-2026-33332","kev_date_added":null,"published":"2026-03-24"},{"cvss_score":6.1,"headline":"NiceGUI has XSS via Code Injection","id":"CVE-2026-27156","kev_date_added":null,"published":"2026-02-24"},{"cvss_score":6.1,"headline":"NiceGUI's XSS vulnerability in ui.markdown() allows arbitrary JavaScript execution through unsanitized HTML content","id":"CVE-2026-25516","kev_date_added":null,"published":"2026-02-06"},{"cvss_score":6.1,"headline":"NiceGUI is vulnerable to XSS via Unescaped URL in ui.navigate.history.push() / replace()","id":"CVE-2026-21871","kev_date_added":null,"published":"2026-01-08"}],"sources":[{"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":"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":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-01-08","vendors":["zauberzeug"]},"summary":"Attackers can execute arbitrary JavaScript in NiceGUI applications via cross-site iframe manipulation of URL fragments.","url":"https://insights.sbomify.com/CVE-2026-21873/"}