# Firefox Developer Edition (en-US) 140.0

Firefox Developer Edition (en-US) 140.0, released June 13, 2025, fixes 12 CVEs in Firefox Developer Edition (en-US). None of them is reported as exploited. Patch Radar priority: Urgent. The latest Firefox Developer Edition (en-US) is 156.0, which also fixes every one of these CVEs.

- Web page: https://patchblox.com/security/fix/windows-app/mozilla.firefox.developeredition-140.0
- Platform: Windows apps
- Released: Jun 13, 2025
- Priority: Urgent (Closes CVE-2025-49710, rated Critical)
- CVEs: 12, exploited: 0, on CISA KEV: 0
- Superseded by: [Firefox Developer Edition (en-US) 156.0](https://patchblox.com/security/data/product/windows-app/firefox-developer-edition-en-us.md), the latest version, which also fixes every CVE listed here

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Firefox Developer Edition (en-US)](https://patchblox.com/security/data/product/windows-app/firefox-developer-edition-en-us.md) |  | 140.0 |

## CVEs this fix closes

| CVE | Priority | Title | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2025-49710](https://patchblox.com/security/data/cve/CVE-2025-49710.md) | Urgent | Integer overflow in OrderedHashTable | 9.8 | 0.0075 |  |
| [CVE-2025-49709](https://patchblox.com/security/data/cve/CVE-2025-49709.md) | Urgent | Memory corruption in canvas surfaces | 9.8 | 0.0067 |  |
| [CVE-2025-6424](https://patchblox.com/security/data/cve/CVE-2025-6424.md) | High | Use-after-free in FontFaceSet | 9.8 | 0.0796 |  |
| [CVE-2025-6436](https://patchblox.com/security/data/cve/CVE-2025-6436.md) | High | Memory safety bugs fixed in Firefox 140 and Thunderbird 140 | 8.1 | 0.0426 |  |
| [CVE-2025-6435](https://patchblox.com/security/data/cve/CVE-2025-6435.md) | High | Save as in Devtools could download files without sanitizing the extension | 8.1 | 0.0046 |  |
| [CVE-2025-6427](https://patchblox.com/security/data/cve/CVE-2025-6427.md) | High | connect-src Content Security Policy restriction could be bypassed | 9.1 | 0.0037 |  |
| [CVE-2025-6429](https://patchblox.com/security/data/cve/CVE-2025-6429.md) | High | Incorrect parsing of URLs could have allowed embedding of youtube.com | 7.5 | 0.0036 |  |
| [CVE-2025-6432](https://patchblox.com/security/data/cve/CVE-2025-6432.md) | High | DNS Requests leaked outside of a configured SOCKS proxy | 8.6 | 0.0035 |  |
| [CVE-2025-6425](https://patchblox.com/security/data/cve/CVE-2025-6425.md) | High | The WebCompat WebExtension shipped with Firefox exposed a persistent UUID | 7.5 | 0.0031 |  |
| [CVE-2025-6433](https://patchblox.com/security/data/cve/CVE-2025-6433.md) | High | WebAuthn would allow a user to sign a challenge on a webpage with an invalid TLS certificate | 9.8 | 0.0030 |  |
| [CVE-2025-6430](https://patchblox.com/security/data/cve/CVE-2025-6430.md) | High | Content-Disposition header ignored when a file is included in an embed or object tag | 7.5 | 0.0027 |  |
| [CVE-2025-6434](https://patchblox.com/security/data/cve/CVE-2025-6434.md) | Routine | HTTPS-Only exception screen lacked anti-clickjacking delay | 4.3 | 0.0028 |  |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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