{"answers":{"affected":"3 open source packages ship an affected version, including github.com/mattermost/mattermost-server. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-20796 in the wild and no public exploit code.","fix":"Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 10.11.10 or 10.11.10+incompatible.","what":"CVE-2026-20796 is a low-severity vulnerability in Mattermost Mattermost Server, published on 13 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-20796 and fix it if it is affected.\n\nWhat it is: CVE-2026-20796 is a low-severity vulnerability in Mattermost Mattermost Server, published on 13 Feb 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-2026-20796 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/mattermost/mattermost-server (Go): affected from 10.11.0; fixed in 10.11.10\n- github.com/mattermost/mattermost-server (Go): affected from 10.11.0; fixed in 10.11.10\n- github.com/mattermost/mattermost-server (Go): affected from 10.11.0+incompatible; fixed in 10.11.10+incompatible\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-2026-20796/ (Markdown: https://insights.sbomify.com/CVE-2026-20796/index.md)","id":"CVE-2026-20796","markdown":"https://insights.sbomify.com/CVE-2026-20796/index.md","name":"CVE-2026-20796","record":{"aliases":["GHSA-2xf7-hmf6-p64j","GO-2026-4495"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"Mattermost collaboration platform","requires_auth":"low_privilege","summary":"A race condition in the common teams API allows deactivated users to access unauthorized team names, requiring an upgrade to Mattermost.","user_interaction":"not_required","vuln_class":"race_condition"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Mattermost","cpe":[{"product":"mattermost_server","vendor":"mattermost"}],"cvss":{"score":3.1,"severity":"low","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-367","name":"Time-of-check Time-of-use (TOCTOU) Race Condition"}],"description":"Mattermost versions 10.11.x \u003c= 10.11.9 fail to properly validate channel membership at the time of data retrieval which allows a deactivated user to learn team names they should not have access to via a race condition in the /common_teams API endpoint.. Mattermost Advisory ID: MMSA-2025-00549","ecosystems":["Go"],"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":"Time-of-check time-of-use vulnerability in common teams API","id":"CVE-2026-20796","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":"mattermost:mattermost_server","products":["mattermost:mattermost_server"],"type":"race_condition","year":"2026"},"n_packages":3,"n_references":1,"next":{"headline":"Copeland XWEB and XWEB Pro Stack-based Buffer Overflow","id":"CVE-2026-20797"},"packages":[{"ecosystem":"Go","fixed":["10.11.10"],"introduced":["10.11.0"],"last_affected":[],"package":"github.com/mattermost/mattermost-server","purl":null,"source":"GHSA-2xf7-hmf6-p64j"},{"ecosystem":"Go","fixed":["10.11.10"],"introduced":["10.11.0"],"last_affected":[],"package":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","source":"GHSA-2xf7-hmf6-p64j"},{"ecosystem":"Go","fixed":["10.11.10+incompatible"],"introduced":["10.11.0+incompatible"],"last_affected":[],"package":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","source":"GO-2026-4495"}],"prev":{"headline":"Denial of service in Intel(R) PROSet/Wireless WiFi Software for Windows","id":"CVE-2026-20795"},"products":["Mattermost"],"published":"2026-02-13","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":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"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":"2026-02-13","vendors":["Mattermost"]},"summary":"A race condition in the common teams API allows deactivated users to access unauthorized team names, requiring an upgrade to Mattermost.","url":"https://insights.sbomify.com/CVE-2026-20796/"}