Exfiltration of hashed SMB credentials on Windows via file:// redirect
Impact
When following a redirect, Electron delays a check for redirecting to file:// URLs from other schemes. The contents of the file is not available to the renderer following the redirect, but if the redirect target is a SMB URL such as file://some.website.com/, then in some cases, Windows will connect to that server and attempt NTLM authentication, which can include sending hashed credentials.
Patches
This issue has been fixed in all current stable versions of Electron. Specifically, these versions contain the fixes:
- 21.0.0-beta.1
- 20.0.1
- 19.0.11
- 18.3.7
We recommend all apps upgrade to the latest stable version of Electron.
Workarounds
If upgrading isn't possible, this issue can be addressed without upgrading by preventing redirects to file:// URLs in the WebContents.on('will-redirect') event, for all WebContents:
app.on('web-contents-created', (e, webContents) => {
webContents.on('will-redirect', (e, url) => {
if (/^file:/.test(url)) e.preventDefault()
})
})
For more information
If you have any questions or comments about this advisory, email us at security@electronjs.org.
Credit
Thanks to user @coolcoolnoworries for reporting this issue.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | electron | < 18.3.7, >= 20.0.0-beta.1, < 20.0.1, >= 19.0.0-beta.1, < 19.0.11 | 18.3.7, 20.0.1, 19.0.11 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:L- Weakness (CWE)
CWE-200, CWE-522- Platform
- npm
- Package
electron- Disclosed
- 10.11.2022
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-p2jh-44qj-pf2v - CC BY 4.0
Vulnerability history: electron
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 72
- First → latest
- 10.2017 10.2026
- Without a fix
- 0
- Exploited in attacks
- 3
Severity breakdown
- Critical 3
- High 26
- Medium 33
- Low 10
Disclosures per year
- 2017: 1
- 2018: 5
- 2019: 0
- 2020: 6
- 2021: 2
- 2022: 7
- 2023: 6
- 2024: 0
- 2025: 3
- 2026: 42
-
Exfiltration of hashed SMB credentials on Windows via file:// redirect this entry
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