ruby-oj — security advisory
Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.3, Oj.load in :object mode reads uninitialized stack memory (and, for long keys, reads out of bounds) when parsing a JSON object whose key is 254 bytes or longer. The interned bytes can surface to the caller, disclosing process stack memory. In ext/oj/intern.c, form_attr() handles the long-key path by allocating a heap buffer, `b`, populating it with the attribute name, and then freeing it — but it passed the uninitialized stack buffer buf (not b) to rb_intern3(). rb_intern3 therefore reads len + 1 bytes of uninitialized stack memory. When the key length is >= 256, it also reads out of bounds past the 256-byte buf. The resulting bytes are interned and can reach the caller via the produced Symbol or via the EncodingError message raised on invalid UTF-8, leaking process stack contents. This issue has been fixed in version 3.17.3.
- Products
- ruby-oj
- Affected versions
- 3.14.2-1, 3.16.12-1, 3.16.15-1, 3.16.16-1, 3.16.3-1, 3.17.0-1, 3.17.1-1
- Fixed versions
- 3.14.2-1+deb12u1, 3.16.3-1+deb13u1, 3.17.3-1
- CVEs
- CVE-2026-54500
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 12:16 UTC · Revision 2
Source evidence
Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.3, Oj.load in :object mode reads uninitialized stack memory (and, for long keys, reads out of bounds) when parsing a JSON object whose key is 254 bytes or longer. The interned bytes can surface to the caller, disclosing process stack memory. In ext/oj/intern.c, form_attr() handles the long-key path by allocating a heap buffer, `b`, populating it with the attribute name, and then freeing it — but it passed the uninitialized stack buffer buf (not b) to rb_intern3(). rb_intern3 therefore reads len + 1 bytes of uninitialized stack memory. When the key length is >= 256, it also reads out of bounds past the 256-byte buf. The resulting bytes are interned and can reach the caller via the produced Symbol or via the EncodingError message raised on invalid UTF-8, leaking process stack contents. This issue has been fixed in version 3.17.3.
osv:DEBIAN-CVE-2026-54500
ruby-oj
Fixed versions: 3.14.2-1+deb12u1
ruby-oj
Fixed versions: 3.16.3-1+deb13u1
ruby-oj
Fixed versions: 3.17.3-1
Complete source record
{
"id": "6bba5e960b6bb45e71816e4f3bc5e2807e916464dc3951b7924d5f746d93298e",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-54500",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-54500",
"summary": "Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.3, Oj.load in :object mode reads uninitialized stack memory (and, for long keys, reads out of bounds) when parsing a JSON object whose key is 254 bytes or longer. The interned bytes can surface to the caller, disclosing process stack memory. In ext/oj/intern.c, form_attr() handles the long-key path by allocating a heap buffer, `b`, populating it with the attribute name, and then freeing it — but it passed the uninitialized stack buffer buf (not b) to rb_intern3(). rb_intern3 therefore reads len + 1 bytes of uninitialized stack memory. When the key length is >= 256, it also reads out of bounds past the 256-byte buf. The resulting bytes are interned and can reach the caller via the produced Symbol or via the EncodingError message raised on invalid UTF-8, leaking process stack contents. This issue has been fixed in version 3.17.3.",
"evidence": "osv:DEBIAN-CVE-2026-54500",
"products": [
{
"name": {
"value": "ruby-oj",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.14.2-1+deb12u1",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "3.14.2-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "ruby-oj",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.16.3-1+deb13u1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "3.16.3-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "ruby-oj",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.17.3-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "3.16.12-1",
"evidence": "/affected/2/versions"
},
{
"value": "3.16.15-1",
"evidence": "/affected/2/versions"
},
{
"value": "3.16.16-1",
"evidence": "/affected/2/versions"
},
{
"value": "3.16.3-1",
"evidence": "/affected/2/versions"
},
{
"value": "3.17.0-1",
"evidence": "/affected/2/versions"
},
{
"value": "3.17.1-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-54500",
"aliases": [
"DEBIAN-CVE-2026-54500"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.14.2-1+deb12u1"
}
]
}
],
"package": {
"name": "ruby-oj",
"purl": "pkg:deb/debian/ruby-oj?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"3.14.2-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54500.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.16.3-1+deb13u1"
}
]
}
],
"package": {
"name": "ruby-oj",
"purl": "pkg:deb/debian/ruby-oj?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"3.16.3-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54500.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.17.3-1"
}
]
}
],
"package": {
"name": "ruby-oj",
"purl": "pkg:deb/debian/ruby-oj?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"3.16.12-1",
"3.16.15-1",
"3.16.16-1",
"3.16.3-1",
"3.17.0-1",
"3.17.1-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54500.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T11:47:27.367993496Z",
"provider": "osv",
"upstream": [
"CVE-2026-54500"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-54500"
]
},
"related_cves": [
{
"value": "CVE-2026-54500",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 450767,
"published_at": "2026-07-01T00:16:32.147+00:00"
}