{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-6517 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2026-6517 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-6517 is a medium-severity vulnerability in Mattermost, published on 15 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-6517 and fix it if it is affected.\n\nWhat it is: CVE-2026-6517 is a medium-severity vulnerability in Mattermost, published on 15 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-6517 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-2026-6517/ (Markdown: https://insights.sbomify.com/CVE-2026-6517/index.md)","id":"CVE-2026-6517","markdown":"https://insights.sbomify.com/CVE-2026-6517/index.md","name":"CVE-2026-6517","record":{"aliases":["GHSA-2wmq-3m94-g4jr"],"analysis":{"component_type":"desktop_application","fix_type":"upgrade","impacts":["data_read","account_takeover"],"network_reachable":"yes","non_default_config":true,"product_category":"Mattermost Desktop App","requires_auth":"low_privilege","summary":"Attackers can intercept NTLM credentials by embedding images routing to external servers, affecting users on servers without image proxy enabled.","user_interaction":"not_required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Mattermost","cpe":[{"product":"mattermost_desktop","vendor":"mattermost"}],"cvss":{"score":6.3,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-522","name":"Insufficiently Protected Credentials"}],"description":"Mattermost Desktop App versions \u003c=6.1 5.5.13.0 fail to restrict the allow list of domains to which NTLM credentials were forwarded to in the Mattermost Desktop App which allows any user on a server without the image proxy enabled to intercept other users credentials via embedding an image that routes to an external web server. Mattermost Advisory ID: MMSA-2026-00651","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":"Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed","id":"CVE-2026-6517","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"information_disclosure","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"File upload in CMP – Coming Soon \u0026 Maintenance Plugin by NiteoThemes","id":"CVE-2026-6518"},"packages":[],"prev":{"headline":"Remote Code Execution","id":"CVE-2026-6516"},"products":["Mattermost"],"published":"2026-06-15","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":"2026-06-15","vendors":["Mattermost"]},"summary":"Attackers can intercept NTLM credentials by embedding images routing to external servers, affecting users on servers without image proxy enabled.","url":"https://insights.sbomify.com/CVE-2026-6517/"}