{"answers":{"affected":"12 open source packages ship an affected version, including github.com/mattermost/mattermost/server/v8, github.com/mattermost/mattermost-server and github.com/mattermost/mattermost-server/v5. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-28741 in the wild and no public exploit code.","fix":"Upgrade github.com/mattermost/mattermost/server/v8 to a fixed version for your release line: 11.3.3, 11.4.3, 11.5.0 or 8.0.0-20260220133927-c29cf05d40f8.","what":"CVE-2026-28741 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 15 Apr 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-2026-28741 and fix it if it is affected.\n\nWhat it is: CVE-2026-28741 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 15 Apr 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-2026-28741 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 11.3.0-rc1; fixed in 11.3.3\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 11.3.0-rc1; fixed in 11.3.3\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 11.4.0-rc1; fixed in 11.4.3\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 11.4.0-rc1; fixed in 11.4.3\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 11.5.0-rc1; fixed in 11.5.0\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 11.5.0-rc1; fixed in 11.5.0\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 8.0.0-20250721062209-4952acea88ce; fixed in 8.0.0-20260220133927-c29cf05d40f8\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 8.0.0-20250721062209-4952acea88ce; fixed in 8.0.0-20260220133927-c29cf05d40f8\n- github.com/mattermost/mattermost/server/v8 (Go): affected from 8.0.0-20250721062209-4952acea88ce; fixed in 8.0.0-20260220133927-c29cf05d40f8\n- github.com/mattermost/mattermost-server (Go): affected from 11.3.0-rc1+incompatible; fixed in 11.3.3+incompatible, 11.4.3+incompatible, 11.5.0+incompatible\n- github.com/mattermost/mattermost-server/v5 (Go): affected all versions; no fix listed\n- github.com/mattermost/mattermost-server/v6 (Go): affected all versions; no fix listed\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-2026-28741/ (Markdown: https://insights.sbomify.com/CVE-2026-28741/index.md)","id":"CVE-2026-28741","markdown":"https://insights.sbomify.com/CVE-2026-28741/index.md","name":"CVE-2026-28741","record":{"aliases":["GHSA-m7cf-4gh2-v4qg","GO-2026-5495"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["account_takeover","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Mattermost collaboration platform","requires_auth":"none","summary":"Attackers can bypass CSRF protection to change a user's authentication method, potentially leading to account takeover.","user_interaction":"required","vuln_class":"csrf"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Mattermost","cpe":[{"product":"mattermost_server","vendor":"mattermost"}],"cvss":{"score":6.8,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-352","name":"Cross-Site Request Forgery"}],"description":"Mattermost versions 10.11.x \u003c= 10.11.12, 11.5.x \u003c= 11.5.0, 11.4.x \u003c= 11.4.2, 11.3.x \u003c= 11.3.2 fail to validate CSRF tokens on an authentication endpoint which allows an attacker to update a user's authentication method via a CSRF attack by tricking a user into visiting a malicious page. Mattermost Advisory ID: MMSA-2026-00625","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":"CSRF Protection Bypass Allows Updating a User's Authentication Method","id":"CVE-2026-28741","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":"mattermost:mattermost_server","products":["mattermost:mattermost_server"],"type":"csrf","year":"2026"},"n_packages":12,"n_references":1,"next":{"headline":"Naxclow IoT Platform Use of hard-coded cryptographic key","id":"CVE-2026-28742"},"packages":[{"ecosystem":"Go","fixed":["11.3.3+incompatible","11.4.3+incompatible","11.5.0+incompatible"],"introduced":["11.3.0-rc1+incompatible","11.4.0-rc1+incompatible","11.5.0-rc1+incompatible"],"last_affected":[],"package":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","source":"GO-2026-5495"},{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":[],"package":"github.com/mattermost/mattermost-server/v5","purl":"pkg:golang/github.com/mattermost/mattermost-server/v5","source":"GO-2026-5495"},{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":[],"package":"github.com/mattermost/mattermost-server/v6","purl":"pkg:golang/github.com/mattermost/mattermost-server/v6","source":"GO-2026-5495"},{"ecosystem":"Go","fixed":["11.3.3"],"introduced":["11.3.0-rc1"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":null,"source":"GHSA-m7cf-4gh2-v4qg"},{"ecosystem":"Go","fixed":["11.3.3"],"introduced":["11.3.0-rc1"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","source":"GHSA-m7cf-4gh2-v4qg"},{"ecosystem":"Go","fixed":["11.4.3"],"introduced":["11.4.0-rc1"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":null,"source":"GHSA-m7cf-4gh2-v4qg"},{"ecosystem":"Go","fixed":["11.4.3"],"introduced":["11.4.0-rc1"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","source":"GHSA-m7cf-4gh2-v4qg"},{"ecosystem":"Go","fixed":["11.5.0"],"introduced":["11.5.0-rc1"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":null,"source":"GHSA-m7cf-4gh2-v4qg"},{"ecosystem":"Go","fixed":["11.5.0"],"introduced":["11.5.0-rc1"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","source":"GHSA-m7cf-4gh2-v4qg"},{"ecosystem":"Go","fixed":["8.0.0-20260220133927-c29cf05d40f8"],"introduced":["8.0.0-20250721062209-4952acea88ce"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":null,"source":"GHSA-m7cf-4gh2-v4qg"},{"ecosystem":"Go","fixed":["8.0.0-20260220133927-c29cf05d40f8"],"introduced":["8.0.0-20250721062209-4952acea88ce"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","source":"GHSA-m7cf-4gh2-v4qg"},{"ecosystem":"Go","fixed":["8.0.0-20260220133927-c29cf05d40f8"],"introduced":["8.0.0-20250721062209-4952acea88ce"],"last_affected":[],"package":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","source":"GO-2026-5495"}],"prev":{"headline":"Gitea LFS object reuse bypasses Code-unit authorization","id":"CVE-2026-28740"},"products":["Mattermost"],"published":"2026-04-15","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":"total"},"state":"PUBLISHED","updated":"2026-04-15","vendors":["Mattermost"]},"summary":"Attackers can bypass CSRF protection to change a user's authentication method, potentially leading to account takeover.","url":"https://insights.sbomify.com/CVE-2026-28741/"}