{"cve":"CVE-2026-4054","nvd":{"published":"2026-05-15T19:17:04.803","modified":"2026-06-17T10:55:54.630","status":"Analyzed","description":"Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header (e.g. image/png) embedded in an og:image meta tag or Markdown image link.. Mattermost Advisory ID: MMSA-2026-00630","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-754"],"references":["https://mattermost.com/security-updates"],"products":["mattermost:mattermost_server"],"source":"nvd","synced_at":"2026-10-19T22:35:16.954578616+00:00"},"epss":{"cve":"CVE-2026-4054","score":0.00242,"percentile":0.15467,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-j76w-p754-g2w7","url":"https://osv.dev/vulnerability/GHSA-j76w-p754-g2w7","summary":"Mattermost doesn't validate the response body of proxied images","modified":"2026-06-25T23:11:39.197468242Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.5.0 <11.5.2"],"fixed":["11.5.2"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=0.0.0-20250731163400-5b955468ea1e <0.0.0-20260414103857-b21ef302025e"],"fixed":["0.0.0-20260414103857-b21ef302025e"]},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=11.4.0 <11.4.4"],"fixed":["11.4.4"]}]},{"id":"GO-2026-5454","url":"https://osv.dev/vulnerability/GO-2026-5454","summary":"Mattermost doesn't validate the response body of proxied images in github.com/mattermost/mattermost-server","modified":"2026-06-25T23:01:17.183161047Z","packages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","purl":"pkg:golang/github.com/mattermost/mattermost-server","ranges":[">=0.0.0-20250731163400-5b955468ea1e <0.0.0-20260414103857-b21ef302025e",">=11.4.0+incompatible <11.4.4+incompatible",">=11.5.0+incompatible <11.5.2+incompatible"],"fixed":["0.0.0-20260414103857-b21ef302025e","11.4.4+incompatible","11.5.2+incompatible"]}]}],"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."]}