Critical
modsecurity-crs — security advisory
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
- Products
- modsecurity-crs
- Affected versions
- 2.2.9-1, 3.0.0-3, 3.0.2-1, 3.1.1-1, 3.2.0-1, 3.3.0-1, 3.3.2-1, 3.3.5-1, 3.3.5-2, 3.3.7-1, 3.3.8-1, 3.3.9-1
- Fixed versions
- Not specified
- CVEs
- CVE-2022-39955
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 00:43 UTC · Revision 1
Source evidence
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
osv:UBUNTU-CVE-2022-39955
modsecurity-crs
Fixed versions: Not specified
modsecurity-crs
Fixed versions: Not specified
modsecurity-crs
Fixed versions: Not specified
modsecurity-crs
Fixed versions: Not specified
modsecurity-crs
Fixed versions: Not specified
modsecurity-crs
Fixed versions: Not specified
modsecurity-crs
Fixed versions: Not specified
modsecurity-crs
Fixed versions: Not specified
Complete source record
{
"id": "d703221db4a81287f465851bba716044d975a7b607e7258a1cce034607a48199",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2022-39955",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2022-39955",
"summary": "The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type \"charset\" names and therefore bypassing the configurable CRS Content-Type header \"charset\" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.",
"evidence": "osv:UBUNTU-CVE-2022-39955",
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"severity": "critical",
"structured": {
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"aliases": [
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],
"metrics": [
{
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"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "Ubuntu",
"score": "low"
}
],
"affected": [
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"events": [
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"package": {
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},
"versions": [
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"3.0.2-1"
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"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
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],
"database_specific": {
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],
"modified": "2026-10-17T12:55:59.206951053Z",
"provider": "osv",
"upstream": [
"CVE-2022-39955"
],
"references": [
"https://ubuntu.com/security/CVE-2022-39955",
"https://coreruleset.org/20220919/crs-version-3-3-3-and-3-2-2-covering-several-cves/",
"https://www.cve.org/CVERecord?id=CVE-2022-39955"
]
},
"related_cves": [
{
"value": "CVE-2022-39955",
"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 354471,
"published_at": "2022-09-20T07:15:00+00:00"
}