{"answers":{"affected":"2 open source packages ship an affected version, including winter/wn-backend-module.","exploited":"There is no known exploitation of CVE-2026-54256 in the wild and no public exploit code.","fix":"Upgrade winter/wn-backend-module to 1.2.13 or later.","what":"CVE-2026-54256 is a medium-severity missing authorization vulnerability in wintercms winter, published on 26 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-54256 and fix it if it is affected.\n\nWhat it is: CVE-2026-54256 is a medium-severity missing authorization vulnerability in wintercms winter, published on 26 Aug 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-2026-54256 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- winter/wn-backend-module (Packagist): affected all versions; fixed in 1.2.13\n- winter/wn-backend-module (Packagist): affected all versions; fixed in 1.2.13\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-2026-54256/ (Markdown: https://insights.sbomify.com/CVE-2026-54256/index.md)","id":"CVE-2026-54256","markdown":"https://insights.sbomify.com/CVE-2026-54256/index.md","name":"CVE-2026-54256","record":{"aliases":["GHSA-3277-h8g9-qj5f"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["data_read","data_modify"],"network_reachable":"yes","non_default_config":false,"product_category":"Winter CMS","requires_auth":"low_privilege","summary":"Authenticated users can read and modify other users' attachment metadata due to missing authorization checks in the FileUpload widget.","user_interaction":"not_required","vuln_class":"missing_authorization"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":5.4,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-639","name":"Authorization Bypass Through User-Controlled Key"},{"id":"CWE-284","name":"Improper Access Control"}],"description":"Winter CMS is a content management system built on the Laravel PHP framework. In versions up to and including 1.2.12, the backend FileUpload form widget trusted an attacker-controlled file_id POST parameter when resolving the attachment it operates on, allowing an authenticated backend user to read and modify attachment records belonging to other users or records. The widget's getFileRecord() lookup resolved the posted id against the global system_files table without verifying that the file belonged to the widget's own relation, parent record, or deferred-binding session. Because all attachments share a single File model and table and attachment ids are sequential integers that are easily enumerated, a user reaching any form with a fileupload field, including the built-in My Account avatar field that requires no specific permission, could target arbitrary attachments to modify their title and description via onSaveAttachmentConfig and change their sort order via onSortAttachments, which passed posted ids straight to an unscoped update. CSRF tokens remain enforced, so exploitation requires a valid authenticated backend session with any level of access. This issue is fixed in version 1.2.13.","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":"Winter: Authenticated IDOR in backend FileUpload widget allows cross-user access to attachment metadata","id":"CVE-2026-54256","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Packagist","product":null,"products":[],"type":"missing_authorization","year":"2026"},"n_packages":2,"n_references":2,"next":{"headline":"Electron: Buffer performs incorrect byte length calculations resulting in heap buffer under/overflow","id":"CVE-2026-54257"},"packages":[{"ecosystem":"Packagist","fixed":["1.2.13"],"introduced":["0"],"last_affected":[],"package":"winter/wn-backend-module","purl":null,"source":"GHSA-3277-h8g9-qj5f"},{"ecosystem":"Packagist","fixed":["1.2.13"],"introduced":["0"],"last_affected":[],"package":"winter/wn-backend-module","purl":"pkg:composer/winter/wn-backend-module","source":"GHSA-3277-h8g9-qj5f"}],"prev":{"headline":"Cyberdrop-DL: Pixeldrain API key shared with unverified thirdparty sites","id":"CVE-2026-54254"},"products":["winter"],"published":"2026-08-26","related":[],"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":"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":"2026-08-27","vendors":["wintercms"]},"summary":"Authenticated users can read and modify other users' attachment metadata due to missing authorization checks in the FileUpload widget.","url":"https://insights.sbomify.com/CVE-2026-54256/"}