CVE-2025-53522Network attack vector

Password-reset email tampering via untrusted Host header

Published Aug 20, 2025 · Updated Aug 20, 2025

Host-header trust in affected Six Apart Movable Type releases allows remote attackers to send password-reset emails with tampered links. The password-reset workflow uses the untrusted HTTP Host header when constructing the email URL instead of restricting it to configured trusted hostnames. No account or user interaction is required to trigger delivery, but the documented consequence is limited to modification of the reset email's destination link.

CVSS severity6.9
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Host-header trust in affected Six Apart Movable Type releases allows remote attackers to send password-reset emails with tampered links. The password-reset workflow uses the untrusted HTTP Host header when constructing the email URL instead of restricting it to configured trusted hostnames. No account or user interaction is required to trigger delivery, but the documented consequence is limited to modification of the reset email's destination link.

The record

CVE
CVE-2025-53522
Published
Aug 20, 2025
Updated
Aug 20, 2025
Vendor
Six Apart Ltd.
Product
Movable Type Advanced
Classifications
CWE-348
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=7 r.5508 and earlier (7 series)
  2. Affected versionversion=8.0.0 to 8.0.6
  3. Affected versionversion=8.4.0 to 8.4.2 (8 series)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Six Apart Ltd. · Movable Type Advancedversion=7 r.5508 and earlier (7 series); version=8.0.0 to 8.0.6; version=8.4.0 to 8.4.2 (8 series)
Six Apart Ltd. · Movable Type Premium (Cloud Edition)version=1.66 (1 series); version=2.09 (2 series)
Six Apart Ltd. · Movable Type Premiumversion=1.66 and earlier (1 series); version=2.09 and earlier (2 series)
Six Apart Ltd. · Movable Type Premium (Advanced Edition)version=1.66 and earlier (1 series); version=2.09 and earlier (2 series)
Six Apart Ltd. · Movable Typeversion=7 r.5508 and earlier (7 series); version=8.0.0 to 8.0.6; version=8.4.0 to 8.4.2 (8 series)
Six Apart Ltd. · Movable Type (Cloud Edition)version=7 r.5508 (7 series); version=8.6.0 (8 series)

Published CVSS scores

5.3JPCERT/CCCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
6.9JPCERT/CCCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-348Use of Less Trusted Source

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo