{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-43991 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2021-43991 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-43991 is a medium-severity cross-site scripting vulnerability in Kentico Xperience, published on 3 Dec 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2021-43991 and fix it if it is affected.\n\nWhat it is: CVE-2021-43991 is a medium-severity cross-site scripting vulnerability in Kentico Xperience, published on 3 Dec 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2021-43991 in the wild and no public exploit code.\n\nAffected product: Kentico Xperience. No package-level version data is available, so check the vendor advisory linked from the reference page.\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-2021-43991/ (Markdown: https://insights.sbomify.com/CVE-2021-43991/index.md)","id":"CVE-2021-43991","markdown":"https://insights.sbomify.com/CVE-2021-43991/index.md","name":"CVE-2021-43991","record":{"aliases":["GHSA-r763-2x4q-j7xx"],"analysis":{"component_type":"web_application","fix_type":"patch","impacts":["account_takeover","data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"Kentico Xperience CMS","requires_auth":"low_privilege","summary":"Attackers can inject persistent scripts via avatar uploads, leading to session hijacking and account takeover for other users.","user_interaction":"required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"AppCheck","cpe":[{"product":"xperience","vendor":"kentico"}],"cvss":{"score":6.8,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"description":"The Kentico Xperience CMS version 13.0 – 13.0.43 is vulnerable to a persistent Cross-Site Scripting (XSS) vulnerability (also known as Stored or Second-Order XSS). Persistent XSS vulnerabilities occur when the application stores and retrieves client supplied data without proper handling of dangerous content. This type of XSS vulnerability is exploited by submitting malicious script content to the application which is then retrieved and executed by other application users. The attacker could exploit this to conduct a range of attacks against users of the affected application such as session hijacking, account take over and accessing sensitive data.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":null,"headline":"Persistent XSS via Avatar Upload in Kentico Xperience CMS","id":"CVE-2021-43991","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"kentico:xperience","products":["kentico:xperience"],"type":"xss","year":"2021"},"n_packages":0,"n_references":1,"next":{"headline":"Incorrect Access Control in Ignition","id":"CVE-2021-43996"},"packages":[],"prev":{"headline":"ICSA-22-109-03 FANUC ROBOGUIDE Simulation Platform","id":"CVE-2021-43990"},"products":["Kentico Xperience XMS"],"published":"2021-12-03","related":[{"cvss_score":9.8,"headline":"Kentico Xperience CMS Authentication Bypass Using an Alternate Path or Channel","id":"CVE-2025-2746","kev_date_added":"2025-10-20","published":"2025-03-24"},{"cvss_score":9.8,"headline":"Kentico Xperience CMS Authentication Bypass Using an Alternate Path or Channel","id":"CVE-2025-2747","kev_date_added":"2025-10-20","published":"2025-03-24"},{"cvss_score":9.8,"headline":"Kentico Xperience Deserialization of Untrusted Data","id":"CVE-2019-10068","kev_date_added":"2022-03-25","published":"2019-03-26"},{"cvss_score":7.2,"headline":"Kentico Xperience Path Traversal","id":"CVE-2025-2749","kev_date_added":"2026-04-20","published":"2025-03-24"},{"cvss_score":9.8,"headline":"Missing authorization in n/a","id":"CVE-2017-17736","kev_date_added":null,"published":"2018-03-23"},{"cvss_score":9.1,"headline":"Missing authorization in n/a","id":"CVE-2019-12102","kev_date_added":null,"published":"2019-05-22"},{"cvss_score":8.8,"headline":"File upload in n/a","id":"CVE-2018-19453","kev_date_added":null,"published":"2019-04-10"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"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":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-04","vendors":["Kentico"]},"summary":"Attackers can inject persistent scripts via avatar uploads, leading to session hijacking and account takeover for other users.","url":"https://insights.sbomify.com/CVE-2021-43991/"}