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SCA: security update for github.com/axllent/mailpit (GHSA-j3fj-qppj-fmmc)

medium Tenable Self-Hosted Container Security Plugin ID 442155

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - Mailpit is an email testing tool and API for developers. The fix for GHSA-6jxm-fv7w-rw5j (CVE-2026-23845,
 "Server-Side Request Forgery (SSRF) via HTML Check API"), shipped in mailpit `v1.28.3`, hardened
 `internal/htmlcheck/css.go::downloadCSSToBytes` with a 5MB size cap, a `text/css` content-type check,
 login-info stripping in `isValidURL`, and an opt-in `--block-remote-css-and-fonts` config flag — but did
 not add the IP-filtering dialer that the same codebase already uses on the two sister SSRF endpoints (the
 proxy handler and link-check). Prior to version 1.30.0, `internal/htmlcheck/css.go::newSafeHTTPClient` is
 mis-named — it builds an `http.Client` whose `Transport.DialContext` calls `net.Dialer.DialContext`
 directly with no IP allowlisting. As a result, the SSRF originally reported by Bao Anh Phan still permits
 the server to dial loopback, private, link-local, and any other reserved/multicast range, provided the
 target replies with `HTTP/200` and a content-type beginning with `text/css`. With redirect-following
 (`CheckRedirect` allows redirects to any `isValidURL` URL with no IP filter), an attacker-controlled
 public site can redirect mailpit's request into the private network without ever appearing in the email's
 HTML. In the default mailpit deploy (no UI auth, no SMTP auth, port 1025/8025 exposed), this is an
 unauthenticated, network-reachable SSRF triggered by sending an HTML email and then issuing one HTTP `GET`
 to `/api/v1/message/{id}/html-check`. Version 1.30.0 contains an updated fix. (CVE-2026-45709)

Solution

Update the github.com/axllent/mailpit library and its related packages to version 1.30.0 or later.

See Also

https://github.com/advisories/GHSA-j3fj-qppj-fmmc

Plugin Details

Severity: Medium

ID: 442155

Version: Revision 1.7

Type: Local

Family: SCA Checks

Published: 5/19/2026

Updated: 7/29/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 1.2

Percentile: 0.01

Vendor

Vendor Severity: Medium

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2026-45709

CVSS v3

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 5.2

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 5/19/2026

Vulnerability Publication Date: 5/14/2026

Reference Information

CVE: CVE-2026-45709

cwe: CWE-918