{"answers":{"affected":"4 open source packages ship an affected version, including Umbraco.Cms. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-31833 in the wild and no public exploit code.","fix":"Upgrade Umbraco.Cms to a fixed version for your release line: 16.5.1 or 17.2.2.","what":"CVE-2026-31833 is a medium-severity cross-site scripting vulnerability in Umbraco Umbraco Cms, published on 10 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-31833 and fix it if it is affected.\n\nWhat it is: CVE-2026-31833 is a medium-severity cross-site scripting vulnerability in Umbraco Umbraco Cms, published on 10 Mar 2026. An attacker needs administrator access to exploit it, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-31833 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- Umbraco.Cms (NuGet): affected from 16.2.0; fixed in 16.5.1\n- Umbraco.Cms (NuGet): affected from 16.2.0; fixed in 16.5.1\n- Umbraco.Cms (NuGet): affected from 17.0.0; fixed in 17.2.2\n- Umbraco.Cms (NuGet): affected from 17.0.0; fixed in 17.2.2\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-2026-31833/ (Markdown: https://insights.sbomify.com/CVE-2026-31833/index.md)","id":"CVE-2026-31833","markdown":"https://insights.sbomify.com/CVE-2026-31833/index.md","name":"CVE-2026-31833","record":{"aliases":["GHSA-vrqc-59mw-qqg7"],"analysis":{"component_type":"cms_plugin","fix_type":"upgrade","impacts":["code_execution","account_takeover"],"network_reachable":"yes","non_default_config":false,"product_category":"Umbraco CMS","requires_auth":"high_privilege","summary":"Authenticated backoffice users can inject malicious HTML into property descriptions due to permissive DOMPurify filtering, leading to stored XSS.","user_interaction":"not_required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"umbraco_cms","vendor":"umbraco"}],"cvss":{"score":6.7,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L","version":"3.1"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"description":"Umbraco is an ASP.NET CMS. From 16.2.0 to before 16.5.1 and 17.2.2, An authenticated backoffice user with access to Settings can inject malicious HTML into property type descriptions. Due to an overly permissive attributeNameCheck configuration (/.+/) in the UFM DOMPurify instance, event handler attributes such as onclick and onload, when used within Umbraco web components (umb-*, uui-*, ufm-*) were not filtered. This vulnerability is fixed in 16.5.1 and 17.2.2.","ecosystems":["NuGet"],"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":"Umbraco has Stored XSS in UFM Rendering Pipeline via Permissive DOMPurify Attribute Filtering","id":"CVE-2026-31833","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"NuGet","product":"umbraco:umbraco_cms","products":["umbraco:umbraco_cms"],"type":"xss","year":"2026"},"n_packages":4,"n_references":1,"next":{"headline":"Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks","id":"CVE-2026-31834"},"packages":[{"ecosystem":"NuGet","fixed":["16.5.1"],"introduced":["16.2.0"],"last_affected":[],"package":"Umbraco.Cms","purl":null,"source":"GHSA-vrqc-59mw-qqg7"},{"ecosystem":"NuGet","fixed":["16.5.1"],"introduced":["16.2.0"],"last_affected":[],"package":"Umbraco.Cms","purl":"pkg:nuget/Umbraco.Cms","source":"GHSA-vrqc-59mw-qqg7"},{"ecosystem":"NuGet","fixed":["17.2.2"],"introduced":["17.0.0"],"last_affected":[],"package":"Umbraco.Cms","purl":null,"source":"GHSA-vrqc-59mw-qqg7"},{"ecosystem":"NuGet","fixed":["17.2.2"],"introduced":["17.0.0"],"last_affected":[],"package":"Umbraco.Cms","purl":"pkg:nuget/Umbraco.Cms","source":"GHSA-vrqc-59mw-qqg7"}],"prev":{"headline":"Umbraco Backoffice API Allows Unauthorized Modification of Domain Data","id":"CVE-2026-31832"},"products":["Umbraco-CMS"],"published":"2026-03-10","related":[{"cvss_score":10,"headline":"Umbraco CMS has an arbitrary file upload vulnerability","id":"CVE-2025-67288","kev_date_added":null,"published":"2025-12-22"},{"cvss_score":9.8,"headline":"File upload in n/a","id":"CVE-2014-10074","kev_date_added":null,"published":"2018-08-27"},{"cvss_score":9.8,"headline":"Server-side request forgery in n/a","id":"CVE-2012-1301","kev_date_added":null,"published":"2017-04-13"},{"cvss_score":9.3,"headline":"Umbraco CMS \u003c 4.7.1 codeEditorSave.asmx RCE","id":"CVE-2012-10054","kev_date_added":null,"published":"2025-08-13"},{"cvss_score":8.8,"headline":"Umbraco has a Management API Vulnerability to Path Traversal With Authenticated Users","id":"CVE-2025-32017","kev_date_added":null,"published":"2025-04-08"},{"cvss_score":8.8,"headline":"Umbraco CMS Authenticated File Upload","id":"CVE-2020-9471","kev_date_added":null,"published":"2020-03-16"},{"cvss_score":8.6,"headline":"Umbraco Remote ApplicationURL Overwrite","id":"CVE-2022-22690","kev_date_added":null,"published":"2022-01-18"}],"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":"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":"total"},"state":"PUBLISHED","updated":"2026-03-11","vendors":["umbraco"]},"summary":"Authenticated backoffice users can inject malicious HTML into property descriptions due to permissive DOMPurify filtering, leading to stored XSS.","url":"https://insights.sbomify.com/CVE-2026-31833/"}