CVE-2018-1000855 json
Cross Site Scripting (XSS) vulnerability in easymon
published 2018-12-20 7 y ago modified 2026-06-17 4 mo ago also GHSA-c289-47qf-rvrr , EUVD-2018-0808
- cvss
- 6.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.9%
- EPSS 0.9% chance of exploitation in 30 days, percentile 59%
- public exploits
- 0
- none known
Summary
easymon version 1.4 and earlier contains a Cross Site Scripting (XSS) vulnerability in Endpoint where monitoring is mounted that can result in Reflected XSS that affects Firefox. Can be used to steal cookies, depending on the cookie settings.. This attack appear to be exploitable via The victim must click on a crafted URL that contains the XSS payload. This vulnerability appears to have been fixed in 1.4.1 and later.
Patch / fix
- rubygems easymon 1.4.1
- github.com/basecamp/easymon#25 pull request
- github.com/basecamp/easymon/issues/26 advisory
Exploit prediction
0.90% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
| GitHub | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| rubygems | easymon | <1.4.1 |
1.4.1 |
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/basecamp/easymon/pull/25
web, patch, third-party-advisory
-
github.com
/basecamp/easymon/issues/26
web, patch, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2018-1000855
advisory
-
github.com
/basecamp/easymon
package
-
github.com
/rubysec/ruby-advisory-db/blob/master/gems/easymon/CVE-2018-1000855.yml
web
Sources
- CVE List CVE-2018-1000855
- GitHub Advisory GHSA-c289-47qf-rvrr
- NVD CVE-2018-1000855
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.