{"cve":"CVE-2026-3590","nvd":{"published":"2026-04-15T12:16:40.023","modified":"2026-06-17T10:43:49.983","status":"Analyzed","description":"Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":6.5},"cwes":["CWE-367"],"references":["https://mattermost.com/security-updates"],"products":["mattermost:mattermost_server"],"source":"nvd","synced_at":"2026-10-19T22:30:49.762551342+00:00"},"epss":{"cve":"CVE-2026-3590","score":0.00152,"percentile":0.04287,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-mh4x-rmrx-3hp4","url":"https://osv.dev/vulnerability/GHSA-mh4x-rmrx-3hp4","summary":"Mattermost has session spoofing due to lack of single-use consumption of guest magic link tokens enforcement","modified":"2026-06-25T23:11:44.105865703Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=8.0.0-20250721062209-4952acea88ce <8.0.0-20250723052842-4cb8d8940332"],"fixed":["8.0.0-20250723052842-4cb8d8940332"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0-rc1 <10.11.13"],"fixed":["10.11.13"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.5.0-rc1 <11.5.0"],"fixed":["11.5.0"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.4.0-rc1 <11.4.3"],"fixed":["11.4.3"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.3.0-rc1 <11.3.3"],"fixed":["11.3.3"]}]},{"id":"GO-2026-5507","url":"https://osv.dev/vulnerability/GO-2026-5507","summary":"Mattermost has session spoofing due to lack of single-use consumption of guest magic link tokens enforcement in github.com/mattermost/mattermost-server","modified":"2026-06-25T23:01:02.100908217Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=10.11.0-rc1+incompatible <10.11.13+incompatible",">=11.3.0-rc1+incompatible <11.3.3+incompatible",">=11.4.0-rc1+incompatible <11.4.3+incompatible",">=11.5.0-rc1+incompatible <11.5.0+incompatible"],"fixed":["10.11.13+incompatible","11.3.3+incompatible","11.4.3+incompatible","11.5.0+incompatible"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server/v5","purl":"pkg:golang/github.com/mattermost/mattermost-server/v5","ranges":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server/v6","purl":"pkg:golang/github.com/mattermost/mattermost-server/v6","ranges":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8","ranges":[">=8.0.0-20250721062209-4952acea88ce <8.0.0-20250723052842-4cb8d8940332"],"fixed":["8.0.0-20250723052842-4cb8d8940332"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}