What is CVE-2018-1000078?

CVE-2018-1000078 is a medium-severity vulnerability in Rubygems, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-03-13.

How severe is CVE-2018-1000078?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2018-1000078 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Rubygems

CVE-2018-1000078

RubyGems version Ruby 2.2 series: 2.2.9 and earlier, Ruby 2.3 series: 2.3.6 and earlier, Ruby 2.4 series: 2.4.3 and earlier, Ruby 2.5 series: 2.5.0 and earlier, prior to trunk revision 62422 contains a Cross Site Scripting (XSS) vulnerability in gem server display of homepage attribute that can result in XSS. This attack appear to be exploitable via the victim must browse to a malicious gem on a vulnerable gem server. This vulnerability appears to have been fixed in 2.7.6.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2018-03-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.027 (85.6th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 85.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.027 · newest: 0.027 · change: 0.000

Affected products

Rubygems
Debian Linux — versions 7.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

www.debian.org/security/2018/dsa-4219 (vendor-advisory)
usn.ubuntu.com/3621-1/ (vendor-advisory)
access.redhat.com/errata/RHSA-2018:3729 (vendor-advisory)
access.redhat.com/errata/RHSA-2018:3730 (vendor-advisory)
lists.debian.org/debian-lts-announce/2018/04/msg00023.html (mailing-list)
access.redhat.com/errata/RHSA-2018:3731 (vendor-advisory)
lists.debian.org/debian-lts-announce/2018/04/msg00001.html (mailing-list, Third Party Advisory)
lists.debian.org/debian-lts-announce/2018/07/msg00012.html (mailing-list)
www.debian.org/security/2018/dsa-4259 (vendor-advisory)
blog.rubygems.org/2018/02/15/2.7.6-released.html (Vendor Advisory)

Frequently asked questions

What is CVE-2018-1000078?: CVE-2018-1000078 is a medium-severity vulnerability in Rubygems, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2018-03-13.
How severe is CVE-2018-1000078?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2018-1000078 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.