{"answers":{"affected":"It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21891 exists.","fix":"No fix has been published for CVE-2026-21891 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-21891 is a critical authentication bypass vulnerability in IceWhaleTech ZimaOS, published on 8 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-21891 and fix it if it is affected.\n\nWhat it is: CVE-2026-21891 is a critical authentication bypass vulnerability in IceWhaleTech ZimaOS, published on 8 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21891 exists.\n\nAffected product: IceWhaleTech ZimaOS. 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-2026-21891/ (Markdown: https://insights.sbomify.com/CVE-2026-21891/index.md)","id":"CVE-2026-21891","markdown":"https://insights.sbomify.com/CVE-2026-21891/index.md","name":"CVE-2026-21891","record":{"aliases":["GHSA-xj93-qw9p-jxq4"],"analysis":{"component_type":"operating_system","fix_type":"no_fix_stated","impacts":["account_takeover"],"network_reachable":"yes","non_default_config":false,"product_category":"ZimaOS operating system","requires_auth":"none","summary":"Attackers can bypass authentication in ZimaOS by using known system service usernames with any password, gaining unauthorized access.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"zimaos","vendor":"zimaspace"}],"cvss":{"score":9.4,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L","version":"3.1"},"cwes":[{"id":"CWE-287","name":"Improper Authentication"}],"description":"ZimaOS is a fork of CasaOS, an operating system for Zima devices and x86-64 systems with UEFI. In versions up to and including 1.5.0, the application checks the validity of the username but appears to skip, misinterpret, or incorrectly validate the password when the provided username matches a known system service account. The application's login function fails to properly handle the password validation result for these users, effectively granting authenticated access to anyone who knows one of these common usernames and provides any password. As of time of publication, no known patched versions are available.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":1,"refs":[{"date":null,"kind":"nuclei","ref":"http/cves/2026/CVE-2026-21891.yaml","stars":null,"title":"ZimaOS - Authentication Bypass"}],"tier":"weaponised"},"has_fix":false,"headline":"ZimaOS has Authentication Bypass via System-Level Username","id":"CVE-2026-21891","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"Parsl Monitoring Visualization Vulnerable to SQL Injection","id":"CVE-2026-21892"},"packages":[],"prev":{"headline":"Weblate leaks information via screenshots","id":"CVE-2026-21889"},"products":["ZimaOS"],"published":"2026-01-08","related":[{"cvss_score":9.1,"headline":"Arbitrary internal service access via /v1/sys/proxy when Cloudflare Tunnel is enabled on ZimaOS","id":"CVE-2026-28798","kev_date_added":null,"published":"2026-04-03"},{"cvss_score":8.6,"headline":"ZimaOS: Arbitrary Deletion of Internal System Files via API Path Manipulation","id":"CVE-2026-28442","kev_date_added":null,"published":"2026-03-05"},{"cvss_score":8.6,"headline":"ZimaOS: Unauthorized Creation of Files/Folders in Restricted System Directories via API","id":"CVE-2026-28286","kev_date_added":null,"published":"2026-03-02"},{"cvss_score":7.5,"headline":"ZimaOS Arbitrary File Read via Parameter Manipulation","id":"CVE-2024-48931","kev_date_added":null,"published":"2024-10-24"},{"cvss_score":7.5,"headline":"ZimaOS (Installed Applications and System Information) has Unauthorized Sensitive Data Leak","id":"CVE-2024-49357","kev_date_added":null,"published":"2024-10-24"},{"cvss_score":7.5,"headline":"ZimaOS vulnerable to Directory Listing via Parameter Manipulation","id":"CVE-2024-49359","kev_date_added":null,"published":"2024-10-24"}],"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)"},{"class":"attribution","licence":"MIT","name":"Nuclei templates"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-01-08","vendors":["IceWhaleTech"]},"summary":"Attackers can bypass authentication in ZimaOS by using known system service usernames with any password, gaining unauthorized access.","url":"https://insights.sbomify.com/CVE-2026-21891/"}