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TI-2026-18216 Aliases CVE-2026-22689GHSA-524m-q5m7-79mm

Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails

Priority LOW 28CWE-1385Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

Mailpit is an email testing tool and API for developers. Prior to version 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim's Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00239 15th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed mailpit (axllent): 1.28.2github.com/axllent/mailpit (Go): 1.28.2, 0.0.0-20260110031614

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
axllentmailpitbefore 1.28.21.28.2Patch availableCNA
—github.com/axllent/mailpit (Go)1.2.6 to before 1.28.21.28.2Patch availableGHSA-524m-q5m7-79mm
—github.com/axllent/mailpit (Go)before 0.0.0-202601100316140.0.0-20260110031614Patch availableGHSA-524m-q5m7-79mm
  • mailpit Vendoraxllent Affected before 1.28.2 Fixed in 1.28.2 Patch available CNA
  • github.com/axllent/mailpit (Go) Vendor— Affected 1.2.6 to before 1.28.2 Fixed in 1.28.2 Patch available GHSA-524m-q5m7-79mm
  • github.com/axllent/mailpit (Go) Vendor— Affected before 0.0.0-20260110031614 Fixed in 0.0.0-20260110031614 Patch available GHSA-524m-q5m7-79mm

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*before 1.28.2Vulnerableaxllent
  • cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:* Versions before 1.28.2 Vulnerable ·axllent

Remediation

  • Fix · CNA mailpit (axllent) Fixed in 1.28.2
  • Fix · GHSA-524m-q5m7-79mm github.com/axllent/mailpit (Go) Fixed in 1.28.2 Advisory →
  • Fix · GHSA-524m-q5m7-79mm github.com/axllent/mailpit (Go) Fixed in 0.0.0-20260110031614 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-22689
  2. 2026-10-03 Alias added: GHSA-524m-q5m7-79mm

References

Exploit 1

Patch 1

Advisory 1

Other 1

  • TI-2026-22161 Mailpit is Vulnerable to Server-Side Request Forgery (SSRF) via Link Check API CVSS 3.1HIGH 8.6
  • TI-2026-33452 Mailpit: Unauthenticated remote memory-exhaustion DoS via unlimited SMTP DATA and /api/v1/send body sizes CVSS 3.1HIGH 7.5
  • TI-2026-33450 Mailpit: Path traversal & arbitrary file write in mailpit dump --http via attacker-controlled message IDs CVSS 3.1HIGH 8.2
  • TI-2026-17561 Mailpit Proxy Endpoint is Vulnerable to Server-Side Request Forgery (SSRF) CVSS 3.1MEDIUM 5.8
  • TI-2026-19194 Mailpit has SMTP Header Injection via Regex Bypass CVSS 3.1MEDIUM 5.3
  • TI-2026-33451 Race condition in axllent mailpit CVSS 3.1MEDIUM 5.9
See all 9 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences