{"answers":{"affected":"It affects 7 products.","exploited":"There is no known exploitation of CVE-2021-3634 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2021-3634 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 31 Aug 2021. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-3634 and fix it if it is affected.\n\nWhat it is: CVE-2021-3634 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 31 Aug 2021. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-3634 in the wild and no public exploit code.\n\nAffected product: Debian Debian Linux. 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-2021-3634/ (Markdown: https://insights.sbomify.com/CVE-2021-3634/index.md)","id":"CVE-2021-3634","markdown":"https://insights.sbomify.com/CVE-2021-3634/index.md","name":"CVE-2021-3634","record":{"aliases":["ALSA-2022:2031","CLSA-2023-1685023099","CLSA-2023-1685023501","DEBIAN-CVE-2021-3634","DSA-4965-1","GHSA-4wwm-f449-qwpq","MGASA-2021-0441","OESA-2021-1343","RHSA-2022:2031","RLSA-2022:2031","UBUNTU-CVE-2021-3634","USN-5053-1"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution","denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"SSH library","requires_auth":"low_privilege","summary":"A memory corruption flaw in libssh allows attackers to execute arbitrary code or cause denial of service via key re-exchange.","user_interaction":"not_required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"redhat","cpe":[{"product":"debian_linux","vendor":"debian"},{"product":"fedora","vendor":"fedoraproject"},{"product":"libssh","vendor":"libssh"},{"product":"cloud_backup","vendor":"netapp"},{"product":"mysql_workbench","vendor":"oracle"},{"product":"enterprise_linux","vendor":"redhat"},{"product":"virtualization","vendor":"redhat"}],"cvss":{"score":6.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-787","name":"Out-of-bounds Write"}],"description":"A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other session_id. Initially, both of them are the same, but after key re-exchange, previous session_id is kept and used as an input to new secret_hash. Historically, both of these buffers had shared length variable, which worked as long as these buffers were same. But the key re-exchange operation can also change the key exchange method, which can be based on hash of different size, eventually creating \"secret_hash\" of different size than the session_id has. This becomes an issue when the session_id memory is zeroed or when it is used again during second key re-exchange.","ecosystems":["AlmaLinux:8","Red Hat:enterprise_linux:8::appstream","Red Hat:enterprise_linux:8::baseos","Rocky Linux:8"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Memory corruption in libssh","id":"CVE-2021-3634","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"debian:debian_linux","products":["debian:debian_linux","fedoraproject:fedora","netapp:cloud_backup","redhat:enterprise_linux","redhat:virtualization"],"type":"memory_corruption","year":"2021"},"n_packages":11,"n_references":8,"next":{"headline":"Denial of service in kernel","id":"CVE-2021-3635"},"packages":[{"ecosystem":"AlmaLinux:8","fixed":["0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh","purl":"pkg:rpm/almalinux/libssh","source":"ALSA-2022:2031"},{"ecosystem":"AlmaLinux:8","fixed":["0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh-config","purl":"pkg:rpm/almalinux/libssh-config","source":"ALSA-2022:2031"},{"ecosystem":"AlmaLinux:8","fixed":["0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh-devel","purl":"pkg:rpm/almalinux/libssh-devel","source":"ALSA-2022:2031"},{"ecosystem":"Red Hat:enterprise_linux:8::appstream","fixed":["0:0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh-debuginfo","purl":"pkg:rpm/redhat/libssh-debuginfo","source":"RHSA-2022:2031"},{"ecosystem":"Red Hat:enterprise_linux:8::appstream","fixed":["0:0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh-debugsource","purl":"pkg:rpm/redhat/libssh-debugsource","source":"RHSA-2022:2031"},{"ecosystem":"Red Hat:enterprise_linux:8::appstream","fixed":["0:0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh-devel","purl":"pkg:rpm/redhat/libssh-devel","source":"RHSA-2022:2031"},{"ecosystem":"Red Hat:enterprise_linux:8::baseos","fixed":["0:0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh","purl":"pkg:rpm/redhat/libssh","source":"RHSA-2022:2031"},{"ecosystem":"Red Hat:enterprise_linux:8::baseos","fixed":["0:0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh-config","purl":"pkg:rpm/redhat/libssh-config","source":"RHSA-2022:2031"},{"ecosystem":"Red Hat:enterprise_linux:8::baseos","fixed":["0:0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh-debuginfo","purl":"pkg:rpm/redhat/libssh-debuginfo","source":"RHSA-2022:2031"},{"ecosystem":"Red Hat:enterprise_linux:8::baseos","fixed":["0:0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh-debugsource","purl":"pkg:rpm/redhat/libssh-debugsource","source":"RHSA-2022:2031"},{"ecosystem":"Rocky Linux:8","fixed":["0:0.9.6-3.el8"],"introduced":["0"],"last_affected":[],"package":"libssh","purl":"pkg:rpm/rocky-linux/libssh?distro=rocky-linux-8\u0026epoch=0","source":"RLSA-2022:2031"}],"prev":{"headline":"Privilege escalation in Driver Management","id":"CVE-2021-3633"},"products":["libssh"],"published":"2021-08-31","related":[{"cvss_score":10,"headline":"ProFTPD Improper Access Control","id":"CVE-2015-3306","kev_date_added":"2026-10-08","published":"2015-05-18"},{"cvss_score":9.9,"headline":"RoundCube Webmail Deserialization of Untrusted Data","id":"CVE-2025-49113","kev_date_added":"2026-02-20","published":"2025-06-02"},{"cvss_score":9.8,"headline":"GNU InetUtils Argument Injection","id":"CVE-2026-24061","kev_date_added":"2026-01-26","published":"2026-01-21"},{"cvss_score":9.8,"headline":"Linux Kernel Improper Check for Unusual or Exceptional Conditions","id":"CVE-2025-39682","kev_date_added":"2026-09-18","published":"2025-09-05"},{"cvss_score":9.8,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2024-9680","kev_date_added":"2024-10-15","published":"2024-10-09"},{"cvss_score":9.8,"headline":"RARLAB UnRAR Directory Traversal","id":"CVE-2022-30333","kev_date_added":"2022-08-09","published":"2022-05-09"},{"cvss_score":9.8,"headline":"Roundcube Webmail SQL Injection","id":"CVE-2021-44026","kev_date_added":"2023-06-22","published":"2021-11-19"}],"sources":[{"class":"attribution","licence":"MIT","name":"AlmaLinux","prefix":"ALSA"},{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"Red Hat","prefix":"RHSA"},{"class":"attribution","licence":"BSD","name":"Rocky Linux","prefix":"RLSA"},{"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)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-03","vendors":["n/a"]},"summary":"A memory corruption flaw in libssh allows attackers to execute arbitrary code or cause denial of service via key re-exchange.","url":"https://insights.sbomify.com/CVE-2021-3634/"}