CVE-2026-45709Public exploitNetwork attack vector

Internal service requests via unfiltered CSS dialer

Published Jul 20, 2026 · Updated Jul 20, 2026

SSRF in the HTML check API in Axllent Mailpit 1.28.3 through 1.29.7 allows remote attackers to issue requests to internal services. The newSafeHTTPClient transport sends CSS fetches and redirects through net.Dialer without rejecting loopback, private, link-local, or reserved addresses. Default deployments require no UI or SMTP authentication; successful requests can invoke state-changing internal GET endpoints or expose a timing oracle.

CVSS severity5.8
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in the HTML check API in Axllent Mailpit 1.28.3 through 1.29.7 allows remote attackers to issue requests to internal services. The newSafeHTTPClient transport sends CSS fetches and redirects through net.Dialer without rejecting loopback, private, link-local, or reserved addresses. Default deployments require no UI or SMTP authentication; successful requests can invoke state-changing internal GET endpoints or expose a timing oracle.

The record

CVE
CVE-2026-45709
Published
Jul 20, 2026
Updated
Jul 20, 2026
Vendor
Axllent
Product
Mailpit
Classifications
CWE-918, T1046, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.28.3, < 1.30.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Axllent · Mailpitversion=>= 1.28.3, < 1.30.0

Published CVSS scores

5.8GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1046Network Service Discovery
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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