{"answers":{"affected":"It affects 4 products.","exploited":"There is no known exploitation of CVE-2021-43539 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2021-43539 is a high-severity use after free vulnerability in Debian Debian Linux, published on 8 Dec 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2021-43539 and fix it if it is affected.\n\nWhat it is: CVE-2021-43539 is a high-severity use after free vulnerability in Debian Debian Linux, published on 8 Dec 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2021-43539 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-2021-43539/ (Markdown: https://insights.sbomify.com/CVE-2021-43539/index.md)","id":"CVE-2021-43539","markdown":"https://insights.sbomify.com/CVE-2021-43539/index.md","name":"CVE-2021-43539","record":{"aliases":["DEBIAN-CVE-2021-43539","GHSA-cx8r-rrrj-cfxg","UBUNTU-CVE-2021-43539"],"analysis":{"component_type":"browser","fix_type":"upgrade","impacts":["code_execution","denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Mozilla Firefox","requires_auth":"none","summary":"A use-after-free vulnerability in Firefox and Thunderbird allows attackers to cause a crash or potentially execute arbitrary code via crafted WebAssembly instances.","user_interaction":"required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mozilla","cpe":[{"product":"debian_linux","vendor":"debian"},{"product":"firefox","vendor":"mozilla"},{"product":"firefox_esr","vendor":"mozilla"},{"product":"thunderbird","vendor":"mozilla"}],"cvss":{"score":8.8,"severity":"high","source":"nvd","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"description":"Failure to correctly record the location of live pointers across wasm instance calls resulted in a GC occurring within the call not tracing those live pointers. This could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Thunderbird \u003c 91.4.0, Firefox ESR \u003c 91.4.0, and Firefox \u003c 95.","ecosystems":[],"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":"Use after free in Firefox","id":"CVE-2021-43539","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"debian:debian_linux","products":["debian:debian_linux","mozilla:firefox","mozilla:firefox_esr","mozilla:thunderbird"],"type":"use_after_free","year":"2021"},"n_packages":0,"n_references":10,"next":{"headline":"Missing authorization in Firefox","id":"CVE-2021-43540"},"packages":[],"prev":{"headline":"Race condition in Firefox","id":"CVE-2021-43538"},"products":["Firefox","Firefox ESR","Thunderbird"],"published":"2021-12-08","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":"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)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-04","vendors":["Mozilla"]},"summary":"A use-after-free vulnerability in Firefox and Thunderbird allows attackers to cause a crash or potentially execute arbitrary code via crafted WebAssembly instances.","url":"https://insights.sbomify.com/CVE-2021-43539/"}