Security readout for executives and security teams
Plain-English summary
CVE-2021-47768 affects ImportExportTools NG 10.0.4, a Thunderbird add-on. A malicious email subject can be stored and later rendered during HTML export, causing injected HTML to run in that exported output. Business risk is mainly to users who export untrusted email to HTML, with potential exposure of local data or session-related information.
Executive priority
Handle as a targeted workflow risk, not an internet-wide emergency. Prioritize teams that use Thunderbird and export email archives to HTML, especially legal, compliance, investigations, or support groups handling external mail. Confirm version exposure and apply vendor guidance when available.
Technical view
The issue is a persistent HTML injection vulnerability in the email export module, classified as CWE-79. Attackers need to deliver a crafted email, and exploitation requires user interaction when the victim exports affected mail to HTML. CVSS 3.1 is 6.1, with network attack vector, low complexity, no privileges, required user interaction, changed scope, and low confidentiality/integrity impact.
Likely exposure
Exposure is limited to environments using ImportExportTools NG version 10.0.4 and exporting emails to HTML. Organizations using Thunderbird without this add-on, using other versions, or not exporting untrusted messages to HTML are less likely to be affected, based on the provided sources.
Exploitation context
Public exploit-oriented references exist, including ExploitDB and Vulnerability-Lab. The provided sources do not show CISA KEV listing or confirmed active exploitation. The attack is not automatic; it depends on a crafted email being present and a user performing an HTML export with the vulnerable add-on.
Researcher notes
The record names ImportExportTools NG 10.0.4 and describes persistent HTML injection through crafted email subjects during HTML export. Sources provide public technical/exploit references, but the bundle does not confirm a fixed version, patch commit, or real-world exploitation. Avoid expanding affected versions without vendor confirmation.
Mitigation direction
- Identify Thunderbird systems with ImportExportTools NG installed.
- Check whether version 10.0.4 is present.
- Review vendor add-on page and repository for current guidance or fixed releases.
- Avoid exporting untrusted or suspicious emails to HTML.
- Treat exported HTML files from mailboxes as untrusted content.
- Remove or disable the add-on where business use is not required.
Validation and detection
- Inventory Thunderbird add-ons across managed endpoints.
- Confirm installed ImportExportTools NG versions.
- Review workflows that export emails or folders to HTML.
- Search mail-security telemetry for suspicious crafted subject lines.
- Verify users are not opening exported HTML from untrusted mail without controls.
- Document compensating controls if no vendor fix is confirmed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-47768 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- ExploitDB-50496CVE reference · exploit
- ImportExportTools NG GitHub RepositoryCVE reference · product
- Thunderbird Addon PageCVE reference · product
- Vulnerability-Lab DisclosureCVE reference · exploit, technical-description
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.