{"answers":{"affected":"It affects 2 products.","exploited":"There is no known exploitation of CVE-2021-26421 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2021-26421 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-26421 is a medium-severity vulnerability in Microsoft Lync Server 2013 CU10, published on 11 May 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2021-26421 and fix it if it is affected.\n\nWhat it is: CVE-2021-26421 is a medium-severity vulnerability in Microsoft Lync Server 2013 CU10, published on 11 May 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2021-26421 in the wild and no public exploit code.\n\nAffected product: Microsoft Lync Server 2013 CU10. 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-2021-26421/ (Markdown: https://insights.sbomify.com/CVE-2021-26421/index.md)","id":"CVE-2021-26421","markdown":"https://insights.sbomify.com/CVE-2021-26421/index.md","name":"CVE-2021-26421","record":{"aliases":["GHSA-w6mv-8x3w-r7w5"],"analysis":{"component_type":"server_software","fix_type":"patch","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Skype for Business Server","requires_auth":"low_privilege","summary":"An attacker can spoof content in Skype for Business and Lync, potentially misleading users about the source of messages.","user_interaction":"required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"microsoft","cpe":[{"product":"lync_server","vendor":"microsoft"},{"product":"skype_for_business_server","vendor":"microsoft"}],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:L/A:N/E:U/RL:O/RC:C","version":"3.1"},"cwes":[],"description":"Skype for Business and Lync Spoofing Vulnerability","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":null,"headline":"Skype for Business and Lync Spoofing Vulnerability","id":"CVE-2021-26421","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"other","year":"2021"},"n_packages":0,"n_references":1,"next":{"headline":"Skype for Business and Lync Remote Code Execution Vulnerability","id":"CVE-2021-26422"},"packages":[],"prev":{"headline":"Microsoft SharePoint Server Remote Code Execution Vulnerability","id":"CVE-2021-26420"},"products":["Microsoft Lync Server 2013 CU10","Skype for Business Server 2015 CU11"],"published":"2021-05-11","related":[{"cvss_score":7.2,"headline":"Skype for Business and Lync Remote Code Execution Vulnerability","id":"CVE-2022-33633","kev_date_added":null,"published":"2022-07-12"},{"cvss_score":7.2,"headline":"Skype for Business and Lync Remote Code Execution Vulnerability","id":"CVE-2021-26422","kev_date_added":null,"published":"2021-05-11"},{"cvss_score":6.5,"headline":"Skype for Business Information Disclosure Vulnerability","id":"CVE-2022-26911","kev_date_added":null,"published":"2022-04-15"},{"cvss_score":6.5,"headline":"Skype for Business and Lync Spoofing Vulnerability","id":"CVE-2021-24073","kev_date_added":null,"published":"2021-02-25"},{"cvss_score":6.5,"headline":"Skype for Business and Lync Denial of Service Vulnerability","id":"CVE-2021-24099","kev_date_added":null,"published":"2021-02-25"},{"cvss_score":6.1,"headline":"Cross-site scripting in Microsoft Lync Server 2013","id":"CVE-2019-0798","kev_date_added":null,"published":"2019-04-09"}],"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":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-03","vendors":["Microsoft"]},"summary":"An attacker can spoof content in Skype for Business and Lync, potentially misleading users about the source of messages.","url":"https://insights.sbomify.com/CVE-2021-26421/"}