{"id":"CVE-2026-3472","aliases":["EUVD-2026-39775","GHSA-8rm3-f79m-54wg"],"status":"published","title":"Markdown image rendering bypass in AI bot tool result posts in Mattermost","description":"Mattermost versions 10.11.x \u003c= 10.11.18, 11.6.x \u003c= 11.6.3, 11.5.x \u003c= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619","severity":{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00271,"percentile":0.19505,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-693"],"published":"2026-06-26T14:42:24Z","modified":"2026-11-07T02:48:27Z","products":[{"vendor":"mattermost","product":"mattermost"},{"vendor":"mattermost","product":"mattermost_server"}],"references":[{"url":"https://mattermost.com/security-updates","tags":["vendor-advisory","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3472","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-8rm3-f79m-54wg"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3472.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-3472","title":"Markdown image rendering bypass in AI bot tool result posts in Mattermost","description":"Mattermost versions 10.11.x \u003c= 10.11.18, 11.6.x \u003c= 11.6.3, 11.5.x \u003c= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619","status":"published","published":"2026-06-26T14:42:24.154Z","modified":"2026-06-26T15:41:09.78Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-693"],"updated_at":"2026-11-02T13:49:09.229322Z"}],"euvd":[{"id":"EUVD-2026-39775","description":"Mattermost versions 10.11.x \u003c= 10.11.18, 11.6.x \u003c= 11.6.3, 11.5.x \u003c= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619","status":"published","published":"2026-06-26T14:42:24Z","modified":"2026-06-26T15:41:09Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T18:20:24.495602Z"}],"ghsa":[{"id":"GHSA-8rm3-f79m-54wg","title":"Mattermost versions 10.11.x \u003c= 10.11.18, 11.6.x \u003c= 11.6.3, 11.5.x \u003c= 11.5.6 fail to properly...","description":"Mattermost versions 10.11.x \u003c= 10.11.18, 11.6.x \u003c= 11.6.3, 11.5.x \u003c= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619","status":"published","published":"2026-06-26T15:32:15Z","modified":"2026-06-26T15:32:21Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-693"],"updated_at":"2026-11-02T15:09:00.559973Z"}],"nvd":[{"id":"CVE-2026-3472","description":"Mattermost versions 10.11.x \u003c= 10.11.18, 11.6.x \u003c= 11.6.3, 11.5.x \u003c= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619","status":"published","published":"2026-06-26T15:16:38.77Z","modified":"2026-06-29T19:27:20.823Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"}],"cwes":["CWE-693"],"updated_at":"2026-11-02T14:12:26.045561Z"}],"osv":[{"id":"CVE-2026-3472","title":"Markdown image rendering bypass in AI bot tool result posts in Mattermost","description":"Mattermost versions 10.11.x \u003c= 10.11.18, 11.6.x \u003c= 11.6.3, 11.5.x \u003c= 11.5.6 fail to properly apply markdown image rendering restrictions to AI bot tool result posts, which allows an authenticated attacker to exfiltrate data to an attacker-controlled server via injecting markdown image syntax into tool result content rendered by a victim's client.. Mattermost Advisory ID: MMSA-2026-00619","status":"published","published":"2026-06-26T14:42:24.154Z","modified":"2026-11-07T02:48:27.767397486Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-693"],"updated_at":"2026-11-07T03:08:04.386615Z"}]}}