CVE-2025-52557Network attack vector

Session hijacking via unsanitized email markup

Published Jun 21, 2025 · Updated Jun 23, 2025

Stored cross-site scripting in Mail0 Zero 0.8 allows remote attackers to hijack authenticated sessions through crafted email content. MailIframe removes only selected dangerous elements, then serializes the remaining DOM without sanitizing executable attributes or other active markup. Execution occurs when an authenticated recipient views the message, allowing attacker-supplied JavaScript to run in the application's origin with that recipient's session.

CVSS severity8.6
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Mail0 Zero 0.8 allows remote attackers to hijack authenticated sessions through crafted email content. MailIframe removes only selected dangerous elements, then serializes the remaining DOM without sanitizing executable attributes or other active markup. Execution occurs when an authenticated recipient views the message, allowing attacker-supplied JavaScript to run in the application's origin with that recipient's session.

The record

CVE
CVE-2025-52557
Published
Jun 21, 2025
Updated
Jun 23, 2025
Vendor
Mail0
Product
Zero
Classifications
CWE-1384, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 21, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 23, 2025Record 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== 0.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mail0 · Zeroversion== 0.8

Published CVSS scores

8.6GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/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-1384Improper Handling of Physical or Environmental Conditions
T1203Exploitation for Client Execution

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

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Your stack

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