# CVE-2017-7839: firefox: Control characters prepended before "javascript:" URLs pasted in the addressbar can cause the leading characters to b...

CVE-2017-7839 is fixed in 4 products on 1 platform, first by firefox 57.0.1+build2-0ubuntu1, released June 11, 2018. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2017-7839
- Priority: Routine
- CVSS: n/a (Low)
- EPSS: 0.0112
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 14, 2017

## Description

Control characters prepended before "javascript:" URLs pasted in the addressbar can cause the leading characters to be ignored and the pasted JavaScript to be executed instead of being blocked. This could be used in social engineering and self-cross-site-scripting (self-XSS) attacks where users are convinced to copy and paste text into the addressbar. This vulnerability affects Firefox < 57.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | firefox Ubuntu 18.04.6 LTS (bionic) | 57.0.1+build2-0ubuntu1 | [firefox 57.0.1+build2-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-57.0.1-build2-0ubuntu1.md) | Jun 11, 2018 |
| Linux | firefox-globalmenu Ubuntu 18.04.6 LTS (bionic) | 57.0.1+build2-0ubuntu1 | [firefox-globalmenu 57.0.1+build2-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-globalmenu-57.0.1-build2-0ubuntu1.md) | Jun 11, 2018 |
| Linux | firefox-mozsymbols Ubuntu 18.04.6 LTS (bionic) | 57.0.1+build2-0ubuntu1 | [firefox-mozsymbols 57.0.1+build2-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-mozsymbols-57.0.1-build2-0ubuntu1.md) | Jun 11, 2018 |
| Linux | firefox-testsuite Ubuntu 18.04.6 LTS (bionic) | 57.0.1+build2-0ubuntu1 | [firefox-testsuite 57.0.1+build2-0ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-firefox-testsuite-57.0.1-build2-0ubuntu1.md) | Jun 11, 2018 |

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Data as of 2026-11-07T12:40:37Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo