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CVE-2026-67448— Mailpit: WebSocket origin check bypass via percent-encoded path (regression of CVE-2026-22689)

Quick assessment

Affected
axllent mailpit
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Mailpit 是面向开发人员的一款邮件测试工具及 API。在版本 1.29.0 至 1.30.6 之间，Mailpit 的 中用于验证来源中间件直接检查原始 是否以 开头，而 Go 的 路由机制则基于 URL 路径的百分号解码（percent-decoded）结果进行匹配；同时， 中配置了 直接返回 。因此，恶意网站可通过请求 （其中 是字母 的 URL 编码），绕过 函数，直接访问 的 WebSocket 处理程序。当用户访问该恶意网站后，攻击者可以从未认证且使用默认配置的 Mailpit 实例中获取实时消息

CVSS 6.5 · Medium EPSS 0.15% · P4

Affected Version Matrix 1

VendorProduct Version RangeStatus
axllent mailpit >= 1.29.0, < 1.30.6 affected
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I. Basic Information for CVE-2026-67448

Vulnerability Information
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Vulnerability Title
Mailpit: WebSocket origin check bypass via percent-encoded path (regression of CVE-2026-22689)
Source: CVE Program / CVE List V5
Vulnerability Description
Mailpit is an email testing tool and API for developers. From 1.29.0 until 1.30.6, Mailpit's server/server.go origin middleware checks the raw RequestURI for the /api/ prefix while Go's ServeMux routes using the percent-decoded URL path, and server/websockets/client.go configures websocket.Upgrader.CheckOrigin to return true. A malicious website can request /%61pi/events, skip corsOriginAccessControl(), reach the /api/events WebSocket handler, and receive live message IDs, Message-Id values, sender and recipient fields, subjects, tags, and body snippets from an unauthenticated default Mailpit instance after the user visits the site. This is a regression of the earlier WebSocket origin protection and does not affect deployments protected by --ui-auth-file. This issue is fixed in version 1.30.6.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
URL编码处理不恰当(Hex编码)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
axllent mailpit >= 1.29.0, < 1.30.6 -

II. Public POCs for CVE-2026-67448

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III. Intelligence Information for CVE-2026-67448

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Patches & Fixes for CVE-2026-67448 (1)

Vendor Advisories for CVE-2026-67448 (1)

Vendor Pages for CVE-2026-67448 (1)

Same Patch Batch · axllent · 2026-08-20 · 4 CVEs total

CVE-2026-67445 5.3 MEDIUM Mailpit: SMTP command parser buffers unbounded command lines before syntax rejection
CVE-2026-67446 5.3 MEDIUM Mailpit: Thumbnail generation decodes unbounded image dimensions before scaling
CVE-2026-67447 5.3 MEDIUM Mailpit: SMTP DATA line reader buffers over-limit input before size enforcement

IV. Related Vulnerabilities

Same product: mailpit
Same vendor: axllent
Same weakness: CWE-177

V. Comments for CVE-2026-67448

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