{"answers":{"affected":"It affects 3 products.","exploited":"Yes. Attackers have exploited CVE-2026-21509 in the wild since at least 26 Jan 2026.","fix":"No fix has been published for CVE-2026-21509 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 16 Feb 2026.","what":"CVE-2026-21509 is a high-severity vulnerability in Microsoft 365 Apps, published on 26 Jan 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-21509 and fix it if it is affected.\n\nWhat it is: CVE-2026-21509 is a high-severity vulnerability in Microsoft 365 Apps, published on 26 Jan 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.\nExploitation: Yes. Attackers have exploited CVE-2026-21509 in the wild since at least 26 Jan 2026.\n\nAffected product: Microsoft 365 Apps. 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-2026-21509/ (Markdown: https://insights.sbomify.com/CVE-2026-21509/index.md)","id":"CVE-2026-21509","markdown":"https://insights.sbomify.com/CVE-2026-21509/index.md","name":"CVE-2026-21509","record":{"aliases":["GHSA-ch84-h92g-mw93"],"analysis":{"component_type":"desktop_application","fix_type":"patch","impacts":["security_bypass"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Microsoft Office","requires_auth":"none","summary":"An attacker can bypass security features in Microsoft Office by exploiting reliance on untrusted inputs, requiring local access.","user_interaction":"required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"microsoft","cpe":[{"product":"365_apps","vendor":"microsoft"},{"product":"office","vendor":"microsoft"},{"product":"office_long_term_servicing_channel","vendor":"microsoft"}],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C","version":"3.1"},"cwes":[{"id":"CWE-807","name":"Reliance on Untrusted Inputs in a Security Decision"}],"description":"Reliance on untrusted inputs in a security decision in Microsoft Office allows an unauthorized attacker to bypass a security feature locally.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":"2026-01-27","github_poc":13,"max_poc_stars":42,"metasploit":0,"nuclei":0,"refs":[{"date":"2026-01-29T00:51:18Z","kind":"github_poc","ref":"https://github.com/gavz/CVE-2026-21509-PoC","stars":42,"title":"Educational PoC for CVE‑2026‑21509 (Microsoft Office security feature bypass). Generates a harmless DOCX with dummy OLE artifacts to study EDR/AV visibility. Not an exploit. For isolated labs only; see README for 7‑Zip inspection steps and mitigation references."},{"date":"2026-01-27T12:03:20Z","kind":"github_poc","ref":"https://github.com/kimstars/Ashwesker-CVE-2026-21509","stars":12,"title":"CVE-2026-21509"},{"date":"2026-03-01T17:00:37Z","kind":"github_poc","ref":"https://github.com/suuhm/CVE-2026-21509-handler","stars":8,"title":"PowerShell script to check, apply, and test the Kill-Bit protection for the CVE-2026-21509 Microsoft Office zero-day vulnerability affecting Office 2016/2019/LTSC."},{"date":"2026-01-31T04:52:13Z","kind":"github_poc","ref":"https://github.com/SimoesCTT/CTT-NFS-Vortex-RCE","stars":3,"title":"New Physics Disclosure This repository contains a full weaponized exploit for **CVE-2026-21509**, targeting the Windows Network File System (NFSv4.1) kernel-mode driver (`nfssvr.sys`). "},{"date":"2026-02-01T17:31:24Z","kind":"github_poc","ref":"https://github.com/SimoesCTT/CTT-MICROSOFT-OFFICE-OLE-MANIFOLD-BYPASS-CVE-2026-21509","stars":3,"title":"CVE-2026-21509 is a critical bypass in the Microsoft Office OLE (Object Linking and Embedding) validation engine. While standard \"laminar\" exploits attempt to manipulate static COM objects, this repository utilizes Theorem 4.2 to achieve a speculative race-condition bypass of the Object Definition Rule (ODR)."},{"date":"2026-02-04T14:13:02Z","kind":"github_poc","ref":"https://github.com/decalage2/detect_CVE-2026-21509","stars":3,"title":"YARA rule and python script to detect potential exploits for the CVE-2026-21509 vulnerability in MS Office"},{"date":"2026-01-29T11:40:30Z","kind":"github_poc","ref":"https://github.com/ksk-itdk/KSK-ITDK-CVE-2026-21509-Mitigation","stars":2,"title":"Powershell script with Detection and Remediation for CVE-2026-21509"},{"date":"2026-01-31T09:50:23Z","kind":"github_poc","ref":"https://github.com/SimoesCTT/SCTT-2026-33-0007-The-OLE-Vortex-Laminar-Bypass-","stars":1,"title":"Microsoft just released emergency patches for CVE-2026-21509, a zero-day in the Office Suite that bypasses OLE/COM mitigations when a user simply opens a file. They think their \"Service-side change\" for Office 2021+ is a solid wall. "}],"tier":"exploited"},"has_fix":null,"headline":"Microsoft Office Security Feature Bypass","id":"CVE-2026-21509","indexable":true,"kev":{"dateAdded":"2026-01-26","dueDate":"2026-02-16","knownRansomwareCampaignUse":"Unknown","product":"Office","requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","vendorProject":"Microsoft","vulnerabilityName":"Microsoft Office Security Feature Bypass Vulnerability"},"kind":"cve","links":{"ecosystem":null,"product":"microsoft:365_apps","products":["microsoft:365_apps","microsoft:office","microsoft:office_long_term_servicing_channel"],"type":"security_feature_bypass","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"Microsoft Windows Shell Protection Mechanism Failure","id":"CVE-2026-21510"},"packages":[],"prev":{"headline":"Windows Storage Elevation of Privilege Vulnerability","id":"CVE-2026-21508"},"products":["Microsoft 365 Apps for Enterprise","Microsoft Office 2016","Microsoft Office 2019","Microsoft Office LTSC 2021","Microsoft Office LTSC 2024"],"published":"2026-01-26","related":[{"cvss_score":9.8,"headline":"Microsoft Outlook Improper Input Validation","id":"CVE-2024-21413","kev_date_added":"2025-02-06","published":"2024-02-13"},{"cvss_score":9.8,"headline":"Microsoft Office Outlook Privilege Escalation","id":"CVE-2023-23397","kev_date_added":"2023-03-14","published":"2023-03-14"},{"cvss_score":8.8,"headline":"Microsoft Project Remote Code Execution Vulnerability","id":"CVE-2024-38189","kev_date_added":"2024-08-13","published":"2024-08-13"},{"cvss_score":8.8,"headline":"Microsoft Outlook Security Feature Bypass","id":"CVE-2023-35311","kev_date_added":"2023-07-11","published":"2023-07-11"},{"cvss_score":7.8,"headline":"Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision","id":"CVE-2026-21514","kev_date_added":"2026-02-10","published":"2026-02-10"},{"cvss_score":7.8,"headline":"Microsoft Excel Security Feature Bypass","id":"CVE-2021-42292","kev_date_added":"2021-11-17","published":"2021-11-10"}],"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":"open","licence":"CC0 1.0","name":"CISA KEV"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":"no","exploitation":"active","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-07-30","vendors":["Microsoft"]},"summary":"An attacker can bypass security features in Microsoft Office by exploiting reliance on untrusted inputs, requiring local access.","url":"https://insights.sbomify.com/CVE-2026-21509/"}