CVE-2026-73572Network attack vectorHinoki check available

Victim-session script execution via unsanitized attachment preview

Published Aug 13, 2026 · Updated Aug 13, 2026

Stored XSS in the Classic Web Client in Zimbra Collaboration before 10.1.17 allows remote attackers to execute JavaScript via attachment preview. The inline-preview path insufficiently sanitizes specific attachment content before rendering it in the user's browser session. An attacker must deliver a crafted email and the recipient must preview its malicious attachment, after which the script enables unauthorized session actions or access to session-visible data.

CVSS severity6.1
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in the Classic Web Client in Zimbra Collaboration before 10.1.17 allows remote attackers to execute JavaScript via attachment preview. The inline-preview path insufficiently sanitizes specific attachment content before rendering it in the user's browser session. An attacker must deliver a crafted email and the recipient must preview its malicious attachment, after which the script enables unauthorized session actions or access to session-visible data.

The record

CVE
CVE-2026-73572
Published
Aug 13, 2026
Updated
Aug 13, 2026
Vendor
Zimbra
Product
Zimbra Collaboration
Classifications
CWE-79, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 13, 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 <10.1.17

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zimbra · Zimbra Collaborationversion=0 <10.1.17

Published CVSS scores

6.1MITRECVSS:3.1/AV:N/AC:L/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 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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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