{"cve":"CVE-2026-23829","nvd":{"published":"2026-01-19T00:15:48.707","modified":"2026-06-17T10:22:10.143","status":"Analyzed","description":"Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate `RCPT TO` and `MAIL FROM` addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (`\\r`) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude `\\r` and `\\n` when used inside a character class. Version 1.28.3 fixes this issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-93","CWE-150"],"references":["https://github.com/axllent/mailpit/commit/36cc06c125954dec6673219dafa084e13cc14534","https://github.com/axllent/mailpit/releases/tag/v1.28.3","https://github.com/axllent/mailpit/security/advisories/GHSA-54wq-72mp-cq7c"],"products":["axllent:mailpit"],"source":"nvd","synced_at":"2026-10-19T22:21:16.563232421+00:00"},"epss":{"cve":"CVE-2026-23829","score":0.01402,"percentile":0.72533,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-54wq-72mp-cq7c","url":"https://osv.dev/vulnerability/GHSA-54wq-72mp-cq7c","summary":"Mailpit has an SMTP Header Injection via Regex Bypass","modified":"2026-02-03T22:41:18.430374Z","packages":[{"ecosystem":"Go","name":"github.com/axllent/mailpit","purl":"pkg:golang/github.com/axllent/mailpit","ranges":["<1.28.3"],"fixed":["1.28.3"]}]},{"id":"GO-2026-4333","url":"https://osv.dev/vulnerability/GO-2026-4333","summary":"Mailpit has an SMTP Header Injection via Regex Bypass in github.com/axllent/mailpit","modified":"2026-03-03T04:57:52.677253Z","packages":[{"ecosystem":"Go","name":"github.com/axllent/mailpit","purl":"pkg:golang/github.com/axllent/mailpit","ranges":["<1.28.3"],"fixed":["1.28.3"]}]}],"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."]}