{"answers":{"affected":"It affects 26 products.","exploited":"There is no known exploitation of CVE-2021-3656 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-3656 is a high-severity vulnerability in Fedoraproject Fedora, published on 4 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-3656 and fix it if it is affected.\n\nWhat it is: CVE-2021-3656 is a high-severity vulnerability in Fedoraproject Fedora, published on 4 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-3656 in the wild and no public exploit code.\n\nAffected product: Fedoraproject Fedora. 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-2021-3656/ (Markdown: https://insights.sbomify.com/CVE-2021-3656/index.md)","id":"CVE-2021-3656","markdown":"https://insights.sbomify.com/CVE-2021-3656/index.md","name":"CVE-2021-3656","record":{"aliases":["DEBIAN-CVE-2021-3656","UBUNTU-CVE-2021-3656"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","data_read","denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"KVM AMD SVM","requires_auth":"low_privilege","summary":"A malicious L1 guest can bypass intercepts to read/write host physical memory, causing crashes, data leaks, or guest-to-host escape.","user_interaction":"not_required","vuln_class":"privilege_escalation"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"redhat","cpe":[{"product":"fedora","vendor":"fedoraproject"},{"product":"linux_kernel","vendor":"linux"},{"product":"3scale_api_management","vendor":"redhat"},{"product":"codeready_linux_builder","vendor":"redhat"},{"product":"enterprise_linux","vendor":"redhat"},{"product":"enterprise_linux_desktop","vendor":"redhat"},{"product":"enterprise_linux_eus","vendor":"redhat"},{"product":"enterprise_linux_for_ibm_z_systems","vendor":"redhat"},{"product":"enterprise_linux_for_ibm_z_systems_eus","vendor":"redhat"},{"product":"enterprise_linux_for_power_big_endian","vendor":"redhat"},{"product":"enterprise_linux_for_power_little_endian","vendor":"redhat"},{"product":"enterprise_linux_for_power_little_endian_eus","vendor":"redhat"},{"product":"enterprise_linux_for_real_time","vendor":"redhat"},{"product":"enterprise_linux_for_real_time_for_nfv","vendor":"redhat"},{"product":"enterprise_linux_for_real_time_for_nfv_tus","vendor":"redhat"},{"product":"enterprise_linux_for_real_time_tus","vendor":"redhat"},{"product":"enterprise_linux_for_scientific_computing","vendor":"redhat"},{"product":"enterprise_linux_server","vendor":"redhat"},{"product":"enterprise_linux_server_aus","vendor":"redhat"},{"product":"enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions","vendor":"redhat"},{"product":"enterprise_linux_server_tus","vendor":"redhat"},{"product":"enterprise_linux_server_update_services_for_sap_solutions","vendor":"redhat"},{"product":"enterprise_linux_workstation","vendor":"redhat"},{"product":"openstack","vendor":"redhat"},{"product":"software_collections","vendor":"redhat"},{"product":"virtualization_host","vendor":"redhat"}],"cvss":{"score":8.8,"severity":"high","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-862","name":"Missing Authorization"}],"description":"A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the \"virt_ext\" field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":"2022-11-05","github_poc":1,"max_poc_stars":2,"metasploit":0,"nuclei":0,"refs":[{"date":"2022-11-05T17:32:47Z","kind":"github_poc","ref":"https://github.com/rami08448/CVE-2021-3656-Demo","stars":2,"title":null}],"tier":"poc_unverified"},"has_fix":true,"headline":"Privilege escalation in KVM","id":"CVE-2021-3656","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"fedoraproject:fedora","products":["fedoraproject:fedora","linux:linux_kernel","redhat:enterprise_linux","redhat:enterprise_linux_desktop","redhat:enterprise_linux_eus","redhat:enterprise_linux_for_ibm_z_systems","redhat:enterprise_linux_for_ibm_z_systems_eus","redhat:enterprise_linux_for_power_little_endian","redhat:enterprise_linux_for_power_little_endian_eus","redhat:enterprise_linux_for_scientific_computing","redhat:enterprise_linux_server","redhat:enterprise_linux_server_aus","redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions","redhat:enterprise_linux_server_tus","redhat:enterprise_linux_workstation","redhat:openstack","redhat:software_collections","redhat:virtualization_host"],"type":"privilege_escalation","year":"2021"},"n_packages":0,"n_references":4,"next":{"headline":"A flaw was found in mbsync versions prior to 1.4.4.","id":"CVE-2021-3657"},"packages":[],"prev":{"headline":"Information disclosure in kernel","id":"CVE-2021-3655"},"products":["KVM"],"published":"2022-03-04","related":[{"cvss_score":9.8,"headline":"PHP-CGI OS Command Injection","id":"CVE-2024-4577","kev_date_added":"2024-06-12","published":"2024-06-09"},{"cvss_score":9.8,"headline":"Grafana Authentication Bypass","id":"CVE-2021-39226","kev_date_added":"2022-08-25","published":"2021-10-05"},{"cvss_score":9.8,"headline":"VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow","id":"CVE-2019-5544","kev_date_added":"2021-11-03","published":"2019-12-06"},{"cvss_score":9.6,"headline":"Google Chromium V8 Type Confusion","id":"CVE-2024-4947","kev_date_added":"2024-05-20","published":"2024-05-15"},{"cvss_score":9.6,"headline":"Google Chromium Visuals Use-After-Free","id":"CVE-2024-4671","kev_date_added":"2024-05-13","published":"2024-05-09"},{"cvss_score":9.6,"headline":"Google Chromium Mojo Insufficient Data Validation","id":"CVE-2022-3075","kev_date_added":"2022-09-08","published":"2022-09-26"},{"cvss_score":9.6,"headline":"Google Chromium Indexed DB API Use-After-Free","id":"CVE-2021-30633","kev_date_added":"2021-11-03","published":"2021-10-08"}],"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":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-03","vendors":["n/a"]},"summary":"A malicious L1 guest can bypass intercepts to read/write host physical memory, causing crashes, data leaks, or guest-to-host escape.","url":"https://insights.sbomify.com/CVE-2021-3656/"}