CVE-2021-47768Public exploitNetwork attack vector

HTML execution via unescaped email subjects

Published Jan 15, 2026 · Updated Jan 15, 2026

Stored HTML injection in ImportExportTools NG 10.0.4 allows remote attackers to execute injected markup during HTML email export. The export module writes attacker-controlled Subject header content into an exported HTML index without HTML encoding or sanitization. Exploitation requires an unauthenticated sender to deliver a crafted email and the recipient to export and preview the HTML; the markup can read or alter data accessible to that page.

CVSS severity5.3
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored HTML injection in ImportExportTools NG 10.0.4 allows remote attackers to execute injected markup during HTML email export. The export module writes attacker-controlled Subject header content into an exported HTML index without HTML encoding or sanitization. Exploitation requires an unauthenticated sender to deliver a crafted email and the recipient to export and preview the HTML; the markup can read or alter data accessible to that page.

The record

CVE
CVE-2021-47768
Published
Jan 15, 2026
Updated
Jan 15, 2026
Vendor
Thunderbird
Product
ImportExportTools NG
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 15, 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=10.0.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Thunderbird · ImportExportTools NGversion=10.0.4

Published CVSS scores

5.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
6.1VulnCheckCVSS: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.

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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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