{"answers":{"affected":"3 open source packages ship an affected version, including mistune. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-59923 exists.","fix":"Upgrade mistune to 3.3.0 or later.","what":"CVE-2026-59923 is a medium-severity cross-site scripting vulnerability in lepture mistune, published on 8 Jul 2026. 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-2026-59923 and fix it if it is affected.\n\nWhat it is: CVE-2026-59923 is a medium-severity cross-site scripting vulnerability in lepture mistune, published on 8 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-59923 exists.\n\nAffected packages and fixed versions:\n- mistune (PyPI): affected all versions; fixed in 3.3.0\n- mistune (PyPI): affected all versions; fixed in 3.3.0\n- mistune (PyPI): affected all versions; fixed in 3.3.0\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-2026-59923/ (Markdown: https://insights.sbomify.com/CVE-2026-59923/index.md)","id":"CVE-2026-59923","markdown":"https://insights.sbomify.com/CVE-2026-59923/index.md","name":"CVE-2026-59923","record":{"aliases":["DEBIAN-CVE-2026-59923","ECHO-18b1-043a-4c2c","GHSA-8c25-4j27-2rv3","PYSEC-2026-2211","UBUNTU-CVE-2026-59923"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"Python Markdown parser","requires_auth":"none","summary":"Attacker can execute arbitrary JavaScript in rendered HTML via percent-encoded URIs in Markdown links or images using the Mistune library.","user_interaction":"required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"mistune","vendor":"mistune_project"}],"cvss":{"score":6.1,"severity":"medium","source":"cna","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":"Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, HTMLRenderer.safe_url() does not block percent-encoded javascript URIs, allowing attacker-supplied Markdown links or images to bypass URL protections and execute script in rendered HTML. This issue is fixed in version 3.3.0.","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":"Mistune: XSS via percent-encoded javascript URI bypass in safe_url()","id":"CVE-2026-59923","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"xss","year":"2026"},"n_packages":3,"n_references":3,"next":{"headline":"Mistune: Arbitrary File Read via Include directive path traversal","id":"CVE-2026-59924"},"packages":[{"ecosystem":"PyPI","fixed":["3.3.0"],"introduced":["0"],"last_affected":[],"package":"mistune","purl":null,"source":"GHSA-8c25-4j27-2rv3"},{"ecosystem":"PyPI","fixed":["3.3.0"],"introduced":["0"],"last_affected":[],"package":"mistune","purl":"pkg:pypi/mistune","source":"GHSA-8c25-4j27-2rv3"},{"ecosystem":"PyPI","fixed":["3.3.0"],"introduced":["0"],"last_affected":[],"package":"mistune","purl":"pkg:pypi/mistune","source":"PYSEC-2026-2211"}],"prev":{"headline":"Mistune plugins/formatting: quadratic-time parsing on long runs of `~~x~~`, `==x==`, and `^^x^^` markers (strikethrough / mark / insert)","id":"CVE-2026-59922"},"products":["mistune"],"published":"2026-07-08","related":[{"cvss_score":7.5,"headline":"Mistune plugins/formatting: quadratic-time parsing on long runs of `~~x~~`, `==x==`, and `^^x^^` markers (strikethrough / mark / insert)","id":"CVE-2026-59922","kev_date_added":null,"published":"2026-07-08"},{"cvss_score":7.5,"headline":"inline_parser: quadratic-time parsing on long runs of `**x**` and `***x***` emphasis pairs","id":"CVE-2026-59925","kev_date_added":null,"published":"2026-07-08"},{"cvss_score":7.5,"headline":"Mistune block_parser: quadratic-time parsing on long lists of repeated reference-link definitions","id":"CVE-2026-59928","kev_date_added":null,"published":"2026-07-08"},{"cvss_score":6.1,"headline":"Mistune renderers/html.safe_url: HARMFUL_PROTOCOLS list misses legacy and chained schemes that historically chain to `javascript:` execution","id":"CVE-2026-59929","kev_date_added":null,"published":"2026-07-08"},{"cvss_score":6.1,"headline":"Mistune Math Plugin XSS Escape Bypass","id":"CVE-2026-44708","kev_date_added":null,"published":"2026-05-26"},{"cvss_score":6.1,"headline":"Mistune Heading ID Attribute Injection XSS","id":"CVE-2026-44897","kev_date_added":null,"published":"2026-05-26"}],"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":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-08","vendors":["lepture"]},"summary":"Attacker can execute arbitrary JavaScript in rendered HTML via percent-encoded URIs in Markdown links or images using the Mistune library.","url":"https://insights.sbomify.com/CVE-2026-59923/"}