CVE-2026-54432Network attack vector

Stored XSS via unescaped attachment MIME type

Published Jul 14, 2026 · Updated Jul 14, 2026

Stored XSS in Roundcube Webmail 1.6.0 through 1.6.16 and 1.7.0 through 1.7.1 allows remote attackers to execute script via a crafted attachment. The mail attachment handler in program/actions/mail/get.php inserts the expected and detected MIME-type strings into an attachment-validation warning without escaping each complete value. The recipient must open an attachment whose declared and detected types trigger that warning, after which the injected script runs in the recipient's Roundcube browser context.

CVSS severity4.7
Medium
EPSS probability0.21%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Roundcube Webmail 1.6.0 through 1.6.16 and 1.7.0 through 1.7.1 allows remote attackers to execute script via a crafted attachment. The mail attachment handler in program/actions/mail/get.php inserts the expected and detected MIME-type strings into an attachment-validation warning without escaping each complete value. The recipient must open an attachment whose declared and detected types trigger that warning, after which the injected script runs in the recipient's Roundcube browser context.

The record

CVE
CVE-2026-54432
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
Roundcube
Product
Roundcube Webmail
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 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=1.6.0 <1.6.17
  2. Affected versionversion=1.7.0 <1.7.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Roundcube · Roundcube Webmailversion=1.6.0 <1.6.17; version=1.7.0 <1.7.2

Published CVSS scores

4.7MITRECVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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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