MediumFix available
ruby-css-parser — security advisory
css_parser is a Ruby CSS parser. Prior to 2.1.0 and 1.22.0, the CSS Parser gem does not validate HTTPS connections, allowing a Man-in-the-Middle (MITM) attacker to inject or modify CSS content when stylesheets are loaded via HTTPS. The connection is established with OpenSSL::SSL::VERIFY_NONE, meaning any HTTPS certificate—even entirely untrusted—will be accepted without validation. This vulnerability is fixed in 2.1.0 and 1.22.0.
- Products
- ruby-css-parser
- Affected versions
- 1.19.0-1, 1.21.1-1, 1.6.0-2, 2.0.0-1
- Fixed versions
- 1.19.0-1+deb13u1, 1.6.0-2+deb12u1, 2.1.0-1
- CVEs
- CVE-2026-44312
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 17:48 UTC · Revision 2
Source evidence
css_parser is a Ruby CSS parser. Prior to 2.1.0 and 1.22.0, the CSS Parser gem does not validate HTTPS connections, allowing a Man-in-the-Middle (MITM) attacker to inject or modify CSS content when stylesheets are loaded via HTTPS. The connection is established with OpenSSL::SSL::VERIFY_NONE, meaning any HTTPS certificate—even entirely untrusted—will be accepted without validation. This vulnerability is fixed in 2.1.0 and 1.22.0.
osv:DEBIAN-CVE-2026-44312
ruby-css-parser
Fixed versions: 1.6.0-2+deb12u1
ruby-css-parser
Fixed versions: 1.19.0-1+deb13u1
ruby-css-parser
Fixed versions: 2.1.0-1
Complete source record
{
"id": "926bcf352c991dce77f1cb3ca20e8217b4acf8596a86c621f4e6d3a280629bcd",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-44312",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-44312",
"summary": "css_parser is a Ruby CSS parser. Prior to 2.1.0 and 1.22.0, the CSS Parser gem does not validate HTTPS connections, allowing a Man-in-the-Middle (MITM) attacker to inject or modify CSS content when stylesheets are loaded via HTTPS. The connection is established with OpenSSL::SSL::VERIFY_NONE, meaning any HTTPS certificate—even entirely untrusted—will be accepted without validation. This vulnerability is fixed in 2.1.0 and 1.22.0.",
"evidence": "osv:DEBIAN-CVE-2026-44312",
"products": [
{
"name": {
"value": "ruby-css-parser",
"evidence": "/affected/0/package/name"
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"prerequisites": [],
"fixed_versions": [
{
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"evidence": "/affected/0/ranges"
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"affected_versions": [
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"evidence": "/affected/0/versions"
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{
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{
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"severity": "medium",
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"aliases": [
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"metrics": [
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"affected": [
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"package": {
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"purl": "pkg:deb/debian/ruby-css-parser?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
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],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44312.json"
},
"ecosystem_specific": {
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{
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"package": {
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"purl": "pkg:deb/debian/ruby-css-parser?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.19.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44312.json"
},
"ecosystem_specific": {
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{
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"package": {
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"purl": "pkg:deb/debian/ruby-css-parser?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.19.0-1",
"1.21.1-1",
"2.0.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44312.json"
},
"ecosystem_specific": {
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}
}
],
"modified": "2026-10-27T09:47:39.891559450Z",
"provider": "osv",
"upstream": [
"CVE-2026-44312"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-44312"
]
},
"related_cves": [
{
"value": "CVE-2026-44312",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 461256,
"published_at": "2026-05-14T17:16:22.393+00:00"
}