{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-84640 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-84640 is a high-severity memory corruption vulnerability in Mozilla Thunderbird, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-84640 and fix it if it is affected.\n\nWhat it is: CVE-2026-84640 is a high-severity memory corruption vulnerability in Mozilla Thunderbird, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-84640 in the wild and no public exploit code.\n\nAffected product: Mozilla Thunderbird. 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-2026-84640/ (Markdown: https://insights.sbomify.com/CVE-2026-84640/index.md)","id":"CVE-2026-84640","markdown":"https://insights.sbomify.com/CVE-2026-84640/index.md","name":"CVE-2026-84640","record":{"aliases":["DEBIAN-CVE-2026-84640","GHSA-2q8r-2ghc-82v8","UBUNTU-CVE-2026-84640"],"analysis":{"component_type":"desktop_application","fix_type":"upgrade","impacts":["denial_of_service","data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"Thunderbird mail client","requires_auth":"none","summary":"A malicious mail header causes a one-byte buffer over-read in Thunderbird, potentially leading to crashes or information disclosure.","user_interaction":"not_required","vuln_class":"memory_corruption"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mozilla","cpe":[{"product":"thunderbird","vendor":"mozilla"}],"cvss":{"score":7.5,"severity":"high","source":"cisa-adp","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-126","name":"Buffer Over-read"}],"description":"A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.","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":"One byte overflow read in mail parser","id":"CVE-2026-84640","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"mozilla:thunderbird","products":["mozilla:thunderbird"],"type":"memory_corruption","year":"2026"},"n_packages":0,"n_references":4,"next":{"headline":"Information disclosure due to malicious IMAP server response","id":"CVE-2026-84641"},"packages":[],"prev":{"headline":"Uninitialized memory in MIME parsing","id":"CVE-2026-84639"},"products":["Thunderbird"],"published":"2026-09-01","related":[{"cvss_score":9.8,"headline":"Ambiguous parsing of mail headers","id":"CVE-2026-92238","kev_date_added":null,"published":"2026-09-15"},{"cvss_score":9.8,"headline":"Calendar invitation attachments could launch local executables","id":"CVE-2026-84637","kev_date_added":null,"published":"2026-09-01"},{"cvss_score":9.8,"headline":"Memory corruption in Thunderbird","id":"CVE-2021-43529","kev_date_added":null,"published":"2023-02-16"},{"cvss_score":9.8,"headline":"Memory corruption in Thunderbird","id":"CVE-2019-11703","kev_date_added":null,"published":"2019-07-23"},{"cvss_score":9.8,"headline":"Memory corruption in Thunderbird","id":"CVE-2019-11704","kev_date_added":null,"published":"2019-07-23"},{"cvss_score":9.8,"headline":"Memory corruption in Thunderbird","id":"CVE-2019-11705","kev_date_added":null,"published":"2019-07-23"},{"cvss_score":9.8,"headline":"Use after free in Thunderbird","id":"CVE-2018-18512","kev_date_added":null,"published":"2019-04-26"}],"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":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-02","vendors":["Mozilla"]},"summary":"A malicious mail header causes a one-byte buffer over-read in Thunderbird, potentially leading to crashes or information disclosure.","url":"https://insights.sbomify.com/CVE-2026-84640/"}