CVE-2026-65053Public exploitNetwork attack vector

Stored XSS via unescaped AppleDouble part name

Published Aug 24, 2026 · Updated Aug 24, 2026

Stored XSS in Horde IMP before 7.2.0 allows remote attackers to execute script in a viewer's session via a crafted email. Appledouble.php's _IMPrender() passes the MIME data part's attacker-supplied name through sprintf into IMP_Mime_Status, whose __toString() inserts it into table markup without HTML escaping. An attacker needs only to send mail, but execution requires a recipient to view the crafted multipart/appledouble message; the payload persists in the mailbox.

CVSS severity5.1
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Horde IMP before 7.2.0 allows remote attackers to execute script in a viewer's session via a crafted email. Appledouble.php's _IMPrender() passes the MIME data part's attacker-supplied name through sprintf into IMP_Mime_Status, whose __toString() inserts it into table markup without HTML escaping. An attacker needs only to send mail, but execution requires a recipient to view the crafted multipart/appledouble message; the payload persists in the mailbox.

The record

CVE
CVE-2026-65053
Published
Aug 24, 2026
Updated
Aug 24, 2026
Vendor
Horde
Product
IMP
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 24, 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=0 <7.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Horde · IMPversion=0 <7.2.0

Published CVSS scores

6.1VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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