{"schemaVersion":3,"id":"CVE-2026-45713","aliases":["GHSA-fpxj-m5q8-fphw","GO-2026-5376"],"status":"published","duplicateOf":null,"title":null,"description":"Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the Mailpit SMTP server has a Server.MaxSize int field that controls the maximum allowed DATA payload size, but the field is never assigned anywhere outside test code, leaving it at Go's zero value (0 ⇒ \"no limit\"). The same applies to the HTTP /api/v1/send endpoint, whose request body is decoded with json.NewDecoder(r.Body) and no http.MaxBytesReader. Because Mailpit's default listeners bind [::]:1025 (SMTP) and [::]:8025 (HTTP), with no authentication required on either, a single network-reachable attacker can push an arbitrarily large message into Mailpit and watch RAM consumption spike with a ~7-10× amplification factor (raw frame → enmime envelope tree → search-text index → zstd-encoded write to SQLite). Repeating the attack — or running it concurrently from multiple connections — drives the process to OOM-kill. Version 1.30.0 contains a patch.","dates":{"published":"2026-07-20T15:01:01.489Z","modified":"2026-07-20T16:16:44.713Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":7.5,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · 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1.30.0","eol":null,"hubHref":"/vendor/axllent/mailpit"},{"vendor":"github.com/axllent","product":"mailpit","name":"github.com/axllent/mailpit","label":"mailpit","ecosystem":"Go","cpePart":null,"purl":"pkg:golang/github.com/axllent/mailpit","purlType":"golang","versions":[{"text":"< 1.30.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.30.0","eol":null,"hubHref":null}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/axllent/mailpit/security/advisories/GHSA-fpxj-m5q8-fphw","label":"github.com/axllent/mailpit/security/advisories/GHSA-fpxj-m5q8-fphw","hostname":"github.com","tags":["X Refsource CONFIRM","WEB","Advisory","Exploit","Vendor Advisory"]},{"url":"https://github.com/axllent/mailpit/releases/tag/v1.30.0","label":"github.com/axllent/mailpit/releases/tag/v1.30.0","hostname":"github.com","tags":["X Refsource MISC","WEB","Release Notes"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45713","label":"nvd.nist.gov/vuln/detail/CVE-2026-45713","hostname":"nvd.nist.gov","tags":["Advisory"]},{"url":"https://github.com/axllent/mailpit","label":"github.com/axllent/mailpit","hostname":"github.com","tags":["PACKAGE"]}],"lineage":{"upstream":[],"downstream":["OPENSUSE-SU-2026:21483-1"],"duplicates":[],"related":["OPENSUSE-SU-2026:21483-1"]},"timeline":[{"kind":"published","date":"2026-07-20T15:01:01.489Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-07-20T16:16:44.713Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":40,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T06:18:26.990Z","stale":false,"partial":false}}