High
Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2018-8778
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 06:58 UTC · Revision 1
Source evidence
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.
osv:CVE-2018-8778
Complete source record
{
"id": "0c85120a5edb2999c6f923708556801b7babbbff9bdb13429d9bfbbb2355edf2",
"url": "https://osv.dev/vulnerability/CVE-2018-8778",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2018-8778",
"summary": "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.",
"evidence": "osv:CVE-2018-8778",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2018-8778",
"aliases": [
"CVE-2018-8778"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/ruby/ruby",
"type": "GIT",
"events": [
{
"introduced": "7393bf6a5cfff63683f36535e293caaa0d4c5be0"
},
{
"fixed": "933bb2b8b57c48dc664fce6d752670e6521a4141"
},
{
"introduced": "d40ea2afa6ff5a6e5befcf342fb7b6dc58796b20"
},
{
"fixed": "9bfe7fc5cb457c7bc8df96115ee70b9035f5d885"
},
{
"introduced": "d4bb726b713658f56e630b6cf817a0155b6f390e"
},
{
"fixed": "a8197e08f58c5f2e6d32a774866e0e0d58749911"
},
{
"introduced": "4e0a512972cdcbfcd5279f1a2a81ba342ed75b6e"
},
{
"fixed": "85883dc393f60adc3043d28899eff3f1ce53b4a5"
},
{
"introduced": "ce0e3fc1b10d1f5c5ad6bc31ba344904345468a2"
},
{
"last_affected": "ce0e3fc1b10d1f5c5ad6bc31ba344904345468a2"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.2.0"
},
{
"fixed": "2.2.10"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.3.0"
},
{
"fixed": "2.3.7"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.4.0"
},
{
"fixed": "2.4.4"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "2.5.0"
},
{
"fixed": "2.5.1"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:ruby-lang:ruby:2.6.0:preview1:*:*:*:*:*:*",
"range": [
{
"introduced": "2.6.0-preview1"
},
{
"last_affected": "2.6.0-preview1"
}
],
"source": "CPE_STRING"
}
]
}
}
],
"versions": [
"2.6.0-preview1",
"v2_6_0_preview1"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-8778.json"
}
}
],
"modified": "2026-10-24T10:30:47.135025025Z",
"provider": "osv",
"references": [
"https://access.redhat.com/errata/RHSA-2018:3729",
"https://access.redhat.com/errata/RHSA-2018:3730",
"https://access.redhat.com/errata/RHSA-2018:3731",
"https://access.redhat.com/errata/RHSA-2019:2028",
"https://lists.debian.org/debian-lts-announce/2018/04/msg00023.html",
"https://lists.debian.org/debian-lts-announce/2018/04/msg00024.html",
"https://lists.debian.org/debian-lts-announce/2018/07/msg00012.html",
"https://usn.ubuntu.com/3626-1/",
"https://www.debian.org/security/2018/dsa-4259",
"https://www.ruby-lang.org/en/news/2018/03/28/buffer-under-read-unpack-cve-2018-8778/",
"https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-2-10-released/",
"https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-3-7-released/",
"https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-4-4-released/",
"https://www.ruby-lang.org/en/news/2018/03/28/ruby-2-5-1-released/"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*",
"cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:*"
],
"vendor_product": "canonical:ubuntu_linux",
"extracted_events": [
{
"range": [
{
"introduced": "14.04"
},
{
"last_affected": "14.04"
},
{
"introduced": "16.04"
},
{
"last_affected": "16.04"
},
{
"introduced": "17.10"
},
{
"last_affected": "17.10"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*",
"cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*",
"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "7.0"
},
{
"last_affected": "7.0"
},
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
},
{
"introduced": "9.0"
},
{
"last_affected": "9.0"
}
],
"source": "CPE_STRING"
}
]
},
{
"cpes": [
"cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux:7.4:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux:7.5:*:*:*:*:*:*:*",
"cpe:2.3:o:redhat:enterprise_linux:7.6:*:*:*:*:*:*:*"
],
"vendor_product": "redhat:enterprise_linux",
"extracted_events": [
{
"range": [
{
"introduced": "6.0"
},
{
"last_affected": "6.0"
},
{
"introduced": "7.0"
},
{
"last_affected": "7.0"
},
{
"introduced": "7.4"
},
{
"last_affected": "7.4"
},
{
"introduced": "7.5"
},
{
"last_affected": "7.5"
},
{
"introduced": "7.6"
},
{
"last_affected": "7.6"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2018-8778",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 436476,
"published_at": "2018-04-03T22:29:00.773+00:00"
}