{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-81921 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-81921 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-81921 is a low-severity authentication bypass vulnerability in Concretecms Concrete Cms, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-81921 and fix it if it is affected.\n\nWhat it is: CVE-2026-81921 is a low-severity authentication bypass vulnerability in Concretecms Concrete Cms, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-81921 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-2026-81921/ (Markdown: https://insights.sbomify.com/CVE-2026-81921/index.md)","id":"CVE-2026-81921","markdown":"https://insights.sbomify.com/CVE-2026-81921/index.md","name":"CVE-2026-81921","record":{"aliases":["GHSA-46mx-9v73-g459"],"analysis":{"component_type":"web_application","fix_type":"patch","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Concrete CMS","requires_auth":"low_privilege","summary":"Deactivated Concrete CMS users can retain API access because OAuth refresh tokens are not checked against account status.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"ConcreteCMS","cpe":[{"product":"concrete_cms","vendor":"concretecms"}],"cvss":{"score":2.3,"severity":"low","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L","version":"4.0"},"cwes":[{"id":"CWE-862","name":"Missing Authorization"}],"description":"Concrete CMS 8.5.3 through 9.5.2 enabled the OAuth 2.0 refresh-token grant using the unmodified upstream League grant, which issued new access tokens from a valid refresh token without re-checking the associated account's active status. A user who obtained a refresh token while active could therefore continue to mint valid access tokens after being deactivated or suspended (uIsActive=0), so deactivating an account did not revoke its API access. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L. 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":"In Concrete CMS 8.5.3 to 9,5,2, OAuth 2.0 Refresh-Token Grant Bypasses Account Status","id":"CVE-2026-81921","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"concretecms:concrete_cms","products":["concretecms:concrete_cms"],"type":"auth_bypass","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"Missing authorization in Concrete CMS","id":"CVE-2026-81922"},"packages":[],"prev":{"headline":"Cross-site request forgery in Concrete CMS","id":"CVE-2026-81920"},"products":["Concrete CMS"],"published":"2026-09-15","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":"partial"},"state":"PUBLISHED","updated":"2026-09-15","vendors":["Concrete CMS"]},"summary":"Deactivated Concrete CMS users can retain API access because OAuth refresh tokens are not checked against account status.","url":"https://insights.sbomify.com/CVE-2026-81921/"}