{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-6850 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-6850 is a medium-severity denial of service vulnerability in Mattermost Mattermost Server, published on 13 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-6850 and fix it if it is affected.\n\nWhat it is: CVE-2026-6850 is a medium-severity denial of service vulnerability in Mattermost Mattermost Server, published on 13 Jul 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-2026-6850 in the wild and no public exploit code.\n\nAffected product: Mattermost Mattermost Server. 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-2026-6850/ (Markdown: https://insights.sbomify.com/CVE-2026-6850/index.md)","id":"CVE-2026-6850","markdown":"https://insights.sbomify.com/CVE-2026-6850/index.md","name":"CVE-2026-6850","record":{"aliases":["GHSA-c8hv-77r5-h5f7","MINI-4hm5-6787-jc6f","MINI-q4rj-3pxh-4wfx"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Mattermost chat platform","requires_auth":"low_privilege","summary":"An authenticated attacker can cause client-side denial of service for all channel users by sending a crafted message attachment that triggers regex backtracking.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Mattermost","cpe":[{"product":"mattermost_server","vendor":"mattermost"}],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-1333","name":"Inefficient Regular Expression Complexity"}],"description":"Mattermost versions 11.7.x \u003c= 11.7.2, 11.6.x \u003c= 11.6.4, 10.11.x \u003c= 10.11.19 fail to validate the length and content of message attachment field values, which allows an authenticated attacker to cause a denial of service for all users in a channel via a post containing a specially crafted payload that triggers catastrophic backtracking in the client-side markdown parser.. Mattermost Advisory ID: MMSA-2026-00658","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":"Crafted message attachment causes client-side denial of service via markdown parser regex backtracking in Mattermost","id":"CVE-2026-6850","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"mattermost:mattermost_server","products":["mattermost:mattermost_server"],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":1,"next":{"headline":"Improper link resolution before file access in Bitdefender Total Security via Link Following (VA-13681)","id":"CVE-2026-6851"},"packages":[],"prev":{"headline":"OS Command Injection in TUBITAK BILGEM's Pardus OS My Computer","id":"CVE-2026-6849"},"products":["Mattermost"],"published":"2026-07-13","related":[{"cvss_score":9.9,"headline":"Account takeover on OAuth/OpenID-enabled servers","id":"CVE-2025-12419","kev_date_added":null,"published":"2025-11-27"},{"cvss_score":9.9,"headline":"Account Takeover via Code Exchange Endpoint","id":"CVE-2025-12421","kev_date_added":null,"published":"2025-11-27"},{"cvss_score":9.9,"headline":"Path Traversal Leading to RCE by Any Authenticated Mattermost User","id":"CVE-2025-4981","kev_date_added":null,"published":"2025-06-20"},{"cvss_score":9.9,"headline":"Arbitrary file read via block duplication in Mattermost Boards","id":"CVE-2025-20051","kev_date_added":null,"published":"2025-02-24"},{"cvss_score":9.9,"headline":"Arbitrary file read in Mattermost Boards via import \u0026 export board archive","id":"CVE-2025-25279","kev_date_added":null,"published":"2025-02-24"},{"cvss_score":9.8,"headline":"Mattermost Server: Insufficient Password-Reset Link Invalidation","id":"CVE-2016-11074","kev_date_added":null,"published":"2020-06-19"},{"cvss_score":9.8,"headline":"Mattermost Server allows attackers to gain privileges by accessing unintended API endpoints with users' credentials","id":"CVE-2017-18885","kev_date_added":null,"published":"2020-06-19"}],"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":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-13","vendors":["Mattermost"]},"summary":"An authenticated attacker can cause client-side denial of service for all channel users by sending a crafted message attachment that triggers regex backtracking.","url":"https://insights.sbomify.com/CVE-2026-6850/"}