{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-3471 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-3471 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-3471 is a medium-severity denial of service vulnerability in Mattermost, published on 18 May 2026. 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-2026-3471 and fix it if it is affected.\n\nWhat it is: CVE-2026-3471 is a medium-severity denial of service vulnerability in Mattermost, published on 18 May 2026. 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-2026-3471 in the wild and no public exploit code.\n\nAffected product: Mattermost. 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-2026-3471/ (Markdown: https://insights.sbomify.com/CVE-2026-3471/index.md)","id":"CVE-2026-3471","markdown":"https://insights.sbomify.com/CVE-2026-3471/index.md","name":"CVE-2026-3471","record":{"aliases":["GHSA-fhqj-97rr-gvhp"],"analysis":{"component_type":"desktop_application","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Mattermost Desktop App","requires_auth":"none","summary":"A malicious server owner can crash the Mattermost Desktop App by triggering a JavaScript URL in a pop-up window.","user_interaction":"required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Mattermost","cpe":[{"product":"mattermost_desktop","vendor":"mattermost"}],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-939","name":"Improper Authorization in Handler for Custom URL Scheme"}],"description":"Mattermost Desktop App versions \u003c=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":false,"headline":"Opening a window with {{javascript:alert()}} as URL causes crash in the Mattermost Desktop App","id":"CVE-2026-3471","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"Markdown image rendering bypass in AI bot tool result posts in Mattermost","id":"CVE-2026-3472"},"packages":[],"prev":{"headline":"Other in Email Security","id":"CVE-2026-3470"},"products":["Mattermost"],"published":"2026-05-18","related":[{"cvss_score":9.8,"headline":"Code injection in n/a","id":"CVE-2016-11064","kev_date_added":null,"published":"2020-06-19"},{"cvss_score":9.8,"headline":"Code injection in n/a","id":"CVE-2019-20856","kev_date_added":null,"published":"2020-06-19"},{"cvss_score":8.8,"headline":"Code injection in n/a","id":"CVE-2019-20861","kev_date_added":null,"published":"2020-06-19"},{"cvss_score":7.6,"headline":"Arbitrary application execution via unvalidated server-controlled URLs in Help menu","id":"CVE-2026-1046","kev_date_added":null,"published":"2026-02-16"},{"cvss_score":7.3,"headline":"Security feature bypass in n/a","id":"CVE-2020-14456","kev_date_added":null,"published":"2020-06-19"},{"cvss_score":6.5,"headline":"Posting a malicious markdown image crashes the Mattermost Desktop App","id":"CVE-2026-8075","kev_date_added":null,"published":"2026-07-17"},{"cvss_score":6.5,"headline":"Overly long URLs crash the Mattermost Desktop App","id":"CVE-2026-8683","kev_date_added":null,"published":"2026-06-15"}],"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":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-18","vendors":["Mattermost"]},"summary":"A malicious server owner can crash the Mattermost Desktop App by triggering a JavaScript URL in a pop-up window.","url":"https://insights.sbomify.com/CVE-2026-3471/"}