{"answers":{"affected":"It affects 3 products.","exploited":"There is no known exploitation of CVE-2021-23953 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2021-23953 is a medium-severity vulnerability in Mozilla Firefox, published on 26 Feb 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-2021-23953 and fix it if it is affected.\n\nWhat it is: CVE-2021-23953 is a medium-severity vulnerability in Mozilla Firefox, published on 26 Feb 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-2021-23953 in the wild and no public exploit code.\n\nAffected product: Mozilla Firefox. 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-2021-23953/ (Markdown: https://insights.sbomify.com/CVE-2021-23953/index.md)","id":"CVE-2021-23953","markdown":"https://insights.sbomify.com/CVE-2021-23953/index.md","name":"CVE-2021-23953","record":{"aliases":["DEBIAN-CVE-2021-23953","GHSA-8w82-qfxh-635c","UBUNTU-CVE-2021-23953"],"analysis":{"component_type":"browser","fix_type":"upgrade","impacts":["data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"Mozilla Firefox","requires_auth":"none","summary":"A crafted PDF can leak cross-origin information in Firefox and Thunderbird, allowing attackers to read sensitive data from other origins.","user_interaction":"required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mozilla","cpe":[{"product":"firefox","vendor":"mozilla"},{"product":"firefox_esr","vendor":"mozilla"},{"product":"thunderbird","vendor":"mozilla"}],"cvss":{"score":4.3,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N","version":"3.1"},"cwes":[],"description":"If a user clicked into a specifically crafted PDF, the PDF reader could be confused into leaking cross-origin information, when said information is served as chunked data. This vulnerability affects Firefox \u003c 85, Thunderbird \u003c 78.7, and Firefox ESR \u003c 78.7.","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":"Information disclosure in Firefox","id":"CVE-2021-23953","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"mozilla:firefox","products":["mozilla:firefox","mozilla:firefox_esr","mozilla:thunderbird"],"type":"information_disclosure","year":"2021"},"n_packages":0,"n_references":4,"next":{"headline":"Memory corruption in Firefox","id":"CVE-2021-23954"},"packages":[],"prev":{"headline":"DO NOT USE THIS CANDIDATE NUMBER.","id":"CVE-2021-23952"},"products":["Firefox","Firefox ESR","Thunderbird"],"published":"2021-02-26","related":[{"cvss_score":10,"headline":"Mozilla Firefox and Thunderbird Sandbox Escape","id":"CVE-2019-11708","kev_date_added":"2022-05-23","published":"2019-07-23"},{"cvss_score":9.8,"headline":"Mozilla Multiple Products Remote Code Execution","id":"CVE-2010-3765","kev_date_added":"2025-10-06","published":"2010-10-27"},{"cvss_score":9.6,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2022-26486","kev_date_added":"2022-03-07","published":"2022-12-22"},{"cvss_score":8.8,"headline":"Mozilla Firefox Use-After-Free","id":"CVE-2022-26485","kev_date_added":"2022-03-07","published":"2022-12-22"},{"cvss_score":8.8,"headline":"Mozilla Firefox and Thunderbird Type Confusion","id":"CVE-2019-11707","kev_date_added":"2022-05-23","published":"2019-07-23"},{"cvss_score":8.1,"headline":"Mozilla Firefox And Thunderbird Use-After-Free","id":"CVE-2020-6819","kev_date_added":"2021-11-03","published":"2020-04-24"},{"cvss_score":8.1,"headline":"Mozilla Firefox And Thunderbird Use-After-Free","id":"CVE-2020-6820","kev_date_added":"2021-11-03","published":"2020-04-24"}],"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":["Mozilla"]},"summary":"A crafted PDF can leak cross-origin information in Firefox and Thunderbird, allowing attackers to read sensitive data from other origins.","url":"https://insights.sbomify.com/CVE-2021-23953/"}