{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-81900 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-81900 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-81900 is a high-severity cross-site scripting vulnerability in Concretecms Concrete Cms, published on 14 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-81900 and fix it if it is affected.\n\nWhat it is: CVE-2026-81900 is a high-severity cross-site scripting vulnerability in Concretecms Concrete Cms, published on 14 Sep 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2026-81900 in the wild and no public exploit code.\n\nAffected product: Concretecms Concrete Cms. 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-2026-81900/ (Markdown: https://insights.sbomify.com/CVE-2026-81900/index.md)","id":"CVE-2026-81900","markdown":"https://insights.sbomify.com/CVE-2026-81900/index.md","name":"CVE-2026-81900","record":{"aliases":["GHSA-c87m-38hc-rc4g"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["code_execution","account_takeover"],"network_reachable":"yes","non_default_config":false,"product_category":"Concrete CMS","requires_auth":"high_privilege","summary":"Stored XSS in Concrete CMS YouTube block allows attackers to execute scripts in visitors' browsers, potentially leading to account takeover.","user_interaction":"required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"ConcreteCMS","cpe":[{"product":"concrete_cms","vendor":"concretecms"}],"cvss":{"score":7.3,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"description":"Concrete CMS before 9.5.3 applied only trim() to the YouTube block's stored width and height values and printed them into iframe HTML attributes without escaping or integer casting, resulting in stored cross-site scripting. A user with edit_block permission could inject an event handler that executed script for visitors rendering the page, acting with administrative privileges where the victim was an administrator. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks sh4d0byss for reporting.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":false,"headline":"Concrete CMS before 9.5.3 is vulnerable to Stored XSS in the YouTube block (vWidth/vHeight)","id":"CVE-2026-81900","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"concretecms:concrete_cms","products":["concretecms:concrete_cms"],"type":"xss","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"Concrete CMS 9.2.0 to 9.5.2 is vulnerable to stored XSS due to missing authorization in the `PUT /pages/{cID}` endpoint","id":"CVE-2026-81901"},"packages":[],"prev":{"headline":"Concrete CMS 9.0 to 9.5.2 is vulnerable to Stored XSS via group folder name on the Members \u003e Groups dashboard","id":"CVE-2026-81899"},"products":["Concrete CMS"],"published":"2026-09-14","related":[{"cvss_score":9.8,"headline":"Concrete CMS allows unauthorized access because directories can be created with insecure permissions","id":"CVE-2023-48648","kev_date_added":null,"published":"2023-11-17"},{"cvss_score":9.8,"headline":"Code injection in concrete CMS","id":"CVE-2022-21829","kev_date_added":null,"published":"2022-06-24"},{"cvss_score":9.8,"headline":"Server-Side Request Forgery vulnerability in concrete5","id":"CVE-2021-22958","kev_date_added":null,"published":"2021-10-07"},{"cvss_score":9.8,"headline":"Path traversal in n/a","id":"CVE-2021-40098","kev_date_added":null,"published":"2021-09-27"},{"cvss_score":9.4,"headline":"Concrete CMS Vulnerable to Relative Path Traversal","id":"CVE-2026-8134","kev_date_added":null,"published":"2026-05-21"},{"cvss_score":9.1,"headline":"Path traversal in Concrete CMS","id":"CVE-2022-30117","kev_date_added":null,"published":"2022-06-24"},{"cvss_score":9.1,"headline":"Deserialization in n/a","id":"CVE-2021-40102","kev_date_added":null,"published":"2021-09-24"}],"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":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-09-15","vendors":["Concrete CMS"]},"summary":"Stored XSS in Concrete CMS YouTube block allows attackers to execute scripts in visitors' browsers, potentially leading to account takeover.","url":"https://insights.sbomify.com/CVE-2026-81900/"}