What is CVE-2018-1000076?

CVE-2018-1000076 is a critical-severity vulnerability in Rubygems, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.8/10. Published 2018-03-13.

How severe is CVE-2018-1000076?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2018-1000076 known to be exploited?

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

Vulnerability in Rubygems

CVE-2018-1000076

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 Improper Verification of Cryptographic Signature vulnerability in package.rb that can result in a mis-signed gem could be installed, as the tarball would contain multiple gem signatures.. This vulnerability appears to have been fixed in 2.7.6.

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

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.029 (86.6th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 87th percentile — 86.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.029 · newest: 0.029 · change: 0.000

Affected products

Rubygems
Debian Linux — versions 7.0

Weakness classification (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

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-2018-1000076?: CVE-2018-1000076 is a critical-severity vulnerability in Rubygems, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.8/10. Published 2018-03-13.
How severe is CVE-2018-1000076?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2018-1000076 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.