{"answers":{"affected":"2 open source packages ship an affected version, including concrete5/concrete5. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-8426 in the wild and no public exploit code.","fix":"Upgrade concrete5/concrete5 to 9.5.1 or later.","what":"CVE-2026-8426 is a high-severity vulnerability in Concretecms Concrete Cms, published on 21 May 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-2026-8426 and fix it if it is affected.\n\nWhat it is: CVE-2026-8426 is a high-severity vulnerability in Concretecms Concrete Cms, published on 21 May 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: There is no known exploitation of CVE-2026-8426 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- concrete5/concrete5 (Packagist): affected all versions; fixed in 9.5.1\n- concrete5/concrete5 (Packagist): affected all versions; fixed in 9.5.1\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-2026-8426/ (Markdown: https://insights.sbomify.com/CVE-2026-8426/index.md)","id":"CVE-2026-8426","markdown":"https://insights.sbomify.com/CVE-2026-8426/index.md","name":"CVE-2026-8426","record":{"aliases":["GHSA-5rj5-gfmr-hrc3"],"analysis":{"component_type":"web_application","fix_type":"patch","impacts":["code_execution"],"network_reachable":"yes","non_default_config":true,"product_category":"Concrete CMS","requires_auth":"none","summary":"An attacker can exploit a CSRF vulnerability in Concrete CMS to overwrite packages and execute arbitrary code if the victim has marketplace connectivity and package installation enabled.","user_interaction":"required","vuln_class":"csrf"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"ConcreteCMS","cpe":[{"product":"concrete_cms","vendor":"concretecms"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-829","name":"Inclusion of Functionality from Untrusted Control Sphere"},{"id":"CWE-352","name":"Cross-Site Request Forgery"}],"description":"Concrete CMS 9.5.0 and below does not validate a CSRF token before processing requests to /dashboard/extend/update/prepare_remote_upgrade/\u003cremoteMPID\u003e. An attacker who controls the remote package returned for a known marketplace item ID can overwrite the package PHP on disk and force its upgrade() method to execute in a single browser navigation. This results in remote code execution as the web server user.   In order to be vulnerable, the victim must be passing canInstallPackages, victim site must be connected to the Concrete marketplace; and the attacker controls the package returned for a marketplace item ID already installed on the victim site. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.5 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks https://github.com/maru1009 for reporting.","ecosystems":["Packagist"],"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":"Concrete CMS does not validate a CSRF token before processing requests to `/dashboard/extend/update/prepare_remote_upgrade/\u003cremoteMPID\u003e`","id":"CVE-2026-8426","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Packagist","product":"concretecms:concrete_cms","products":["concretecms:concrete_cms"],"type":"csrf","year":"2026"},"n_packages":2,"n_references":1,"next":{"headline":"Concrete CMS is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file removeFavoriteFolder($id)","id":"CVE-2026-8427"},"packages":[{"ecosystem":"Packagist","fixed":["9.5.1"],"introduced":["0"],"last_affected":[],"package":"concrete5/concrete5","purl":null,"source":"GHSA-5rj5-gfmr-hrc3"},{"ecosystem":"Packagist","fixed":["9.5.1"],"introduced":["0"],"last_affected":[],"package":"concrete5/concrete5","purl":"pkg:composer/concrete5/concrete5","source":"GHSA-5rj5-gfmr-hrc3"}],"prev":{"headline":"Notify Odoo \u003c= 1.0.1 - Cross-Site Request Forgery to Settings Update","id":"CVE-2026-8425"},"products":["Concrete CMS"],"published":"2026-05-21","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":"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":"2026-05-22","vendors":["Concrete CMS"]},"summary":"An attacker can exploit a CSRF vulnerability in Concrete CMS to overwrite packages and execute arbitrary code if the victim has marketplace connectivity and package installation enabled.","url":"https://insights.sbomify.com/CVE-2026-8426/"}