{"answers":{"affected":"It affects 1 product.","exploited":"Yes. Attackers have exploited CVE-2021-42321 in the wild since at least 17 Nov 2021, including in ransomware campaigns.","fix":"No fix has been published for CVE-2021-42321 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 1 Dec 2021.","what":"CVE-2021-42321 is a high-severity code injection vulnerability in Microsoft Exchange Server, published on 10 Nov 2021. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-42321 and fix it if it is affected.\n\nWhat it is: CVE-2021-42321 is a high-severity code injection vulnerability in Microsoft Exchange Server, published on 10 Nov 2021. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: Yes. Attackers have exploited CVE-2021-42321 in the wild since at least 17 Nov 2021, including in ransomware campaigns.\n\nAffected product: Microsoft Exchange Server. 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-2021-42321/ (Markdown: https://insights.sbomify.com/CVE-2021-42321/index.md)","id":"CVE-2021-42321","markdown":"https://insights.sbomify.com/CVE-2021-42321/index.md","name":"CVE-2021-42321","record":{"aliases":["GHSA-3f87-66x4-f3p7"],"analysis":{"component_type":"server_software","fix_type":"patch","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"Microsoft Exchange Server","requires_auth":"low_privilege","summary":"Attackers can execute arbitrary code on Microsoft Exchange Server, requiring immediate patching by administrators.","user_interaction":"not_required","vuln_class":"code_injection"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"microsoft","cpe":[{"product":"exchange_server","vendor":"microsoft"}],"cvss":{"score":8.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","version":"3.1"},"cwes":[],"description":"Microsoft Exchange Server Remote Code Execution Vulnerability","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":"2021-11-23","github_poc":3,"max_poc_stars":83,"metasploit":1,"nuclei":0,"refs":[{"date":"2021-11-23T02:26:26Z","kind":"github_poc","ref":"https://github.com/DarkSprings/CVE-2021-42321","stars":83,"title":"Microsoft Exchange Server Poc"},{"date":"2022-10-08T13:00:23Z","kind":"github_poc","ref":"https://github.com/7BitsTeam/exch_CVE-2021-42321","stars":10,"title":null},{"date":"2021-12-09","kind":"metasploit","ref":"exploit/windows/http/exchange_chainedserializationbinder_rce","stars":null,"title":"Microsoft Exchange Server ChainedSerializationBinder RCE"},{"date":"2022-01-05T23:15:55Z","kind":"github_poc","ref":"https://github.com/timb-machine-mirrors/testanull-CVE-2021-42321_poc.py","stars":0,"title":"Clone from gist"}],"tier":"exploited"},"has_fix":null,"headline":"Microsoft Exchange Server Remote Code Execution","id":"CVE-2021-42321","indexable":true,"kev":{"dateAdded":"2021-11-17","dueDate":"2021-12-01","knownRansomwareCampaignUse":"Known","product":"Exchange","requiredAction":"Apply updates per vendor instructions.","vendorProject":"Microsoft","vulnerabilityName":"Microsoft Exchange Server Remote Code Execution Vulnerability"},"kind":"cve","links":{"ecosystem":null,"product":"microsoft:exchange_server","products":["microsoft:exchange_server"],"type":"code_injection","year":"2021"},"n_packages":0,"n_references":1,"next":{"headline":"Visual Studio Code Elevation of Privilege Vulnerability","id":"CVE-2021-42322"},"packages":[],"prev":{"headline":"Microsoft SharePoint Server Spoofing Vulnerability","id":"CVE-2021-42320"},"products":["Microsoft Exchange Server 2016 Cumulative Update 21","Microsoft Exchange Server 2016 Cumulative Update 22","Microsoft Exchange Server 2019 Cumulative Update 10","Microsoft Exchange Server 2019 Cumulative Update 11"],"published":"2021-11-10","related":[{"cvss_score":9.8,"headline":"Microsoft Exchange Server Privilege Escalation","id":"CVE-2024-21410","kev_date_added":"2024-02-15","published":"2024-02-13"},{"cvss_score":9.1,"headline":"Microsoft Exchange Server Remote Code Execution","id":"CVE-2021-34473","kev_date_added":"2021-11-03","published":"2021-07-14"},{"cvss_score":9.1,"headline":"Microsoft Exchange Server Remote Code Execution","id":"CVE-2021-26855","kev_date_added":"2021-11-03","published":"2021-03-02"},{"cvss_score":9,"headline":"Microsoft Exchange Server Privilege Escalation","id":"CVE-2021-34523","kev_date_added":"2021-11-03","published":"2021-07-14"},{"cvss_score":8.8,"headline":"Microsoft Exchange Server Deserialization of Untrusted Data","id":"CVE-2023-21529","kev_date_added":"2026-04-13","published":"2023-02-14"},{"cvss_score":8.8,"headline":"Microsoft Exchange Server Privilege Escalation","id":"CVE-2022-41080","kev_date_added":"2023-01-10","published":"2022-11-09"},{"cvss_score":8.8,"headline":"Microsoft Exchange Server Server-Side Request Forgery","id":"CVE-2022-41040","kev_date_added":"2022-09-30","published":"2022-10-03"}],"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":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"attribution","licence":"BSD-3-Clause","name":"Metasploit"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":"no","exploitation":"active","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-08-19","vendors":["Microsoft"]},"summary":"Attackers can execute arbitrary code on Microsoft Exchange Server, requiring immediate patching by administrators.","url":"https://insights.sbomify.com/CVE-2021-42321/"}