Is CVE-2018-8778 being actively exploited?

CVE-2018-8778 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2018-8778?

CVE-2018-8778 has a CVSS 3.0 base score of 7.5 (HIGH).

CVE-2018-8778

HIGH · CVSS 7.5EPSS 7.5%EU EUVD

In Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1, an attacker controlling the unpacking format (similar to format string vulnerabilities) can trigger a buffer under-read in the String#unpack method, resulting in a massive and controlled information disclosure.

Key facts

CVSS score: 7.5 (v3.0)
Severity: HIGH
CVSS vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE): CWE-134
EPSS score: 7.5% (94th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2018-20387)
Published: April 3, 2018
NVD last modified: June 17, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2018-20387 in the EU Vulnerability Database. Last updated in EUVD on August 5, 2024.

View on the EU Vulnerability Database

Affected products

canonical / ubuntu linux
canonical / ubuntu linux
canonical / ubuntu linux
debian / debian linux
debian / debian linux
debian / debian linux
redhat / enterprise linux
redhat / enterprise linux
redhat / enterprise linux
redhat / enterprise linux
redhat / enterprise linux
ruby-lang / ruby
ruby-lang / ruby

Certified products that may be affected

8 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Red Hat Enterprise Linux 7 NSS Cryptographic Module - Red Hat®, Inc. - FIPS 140 4498 - historical
Red Hat Enterprise Linux 7 Kernel Crypto API Cryptographic Module - Red Hat®, Inc. - FIPS 140 3939 - historical
Red Hat Enterprise Linux 7 OpenSSH Server Cryptographic Module - Red Hat®, Inc. - FIPS 140 3891 - historical
Red Hat Enterprise Linux 7 OpenSSH Client Cryptographic Module - Red Hat®, Inc. - FIPS 140 3892 - historical
Red Hat Enterprise Linux 7 OpenSSL Cryptographic Module - Red Hat®, Inc. - FIPS 140 3867 - historical

See all 8 in the Security Certifications Explorer.

References

http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00036.html
http://www.securityfocus.com/bid/103693(Third Party Advisory, VDB Entry)
http://www.securitytracker.com/id/1042004(Third Party Advisory, VDB Entry)
https://access.redhat.com/errata/RHSA-2018:3729(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2018:3730(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2018:3731(Third Party Advisory)
https://access.redhat.com/errata/RHSA-2019:2028
https://lists.debian.org/debian-lts-announce/2018/04/msg00023.html(Mailing List, Third Party Advisory)
https://lists.debian.org/debian-lts-announce/2018/04/msg00024.html(Mailing List, Third Party Advisory)
https://lists.debian.org/debian-lts-announce/2018/07/msg00012.html(Mailing List, Third Party Advisory)
https://usn.ubuntu.com/3626-1/(Third Party Advisory)
https://www.debian.org/security/2018/dsa-4259(Third Party Advisory)
https://www.ruby-lang.org/en/news/2018/03/28/buffer-under-read-unpack-cve-2018-8778/(Vendor Advisory)
https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-2-10-released/(Patch, Vendor Advisory)
https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-3-7-released/(Patch, Vendor Advisory)
https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-4-4-released/(Patch, Vendor Advisory)
https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-5-1-released/(Patch, Vendor Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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