CVE-2026-33691 (GCVE-0-2026-33691)
Vulnerability from cvelistv5
Published
2026-04-02 15:03
Modified
2026-04-18 19:16
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-178 - Improper Handling of Case Sensitivity
Summary
The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 3.3.9 and 4.25.0, a bypass was identified in OWASP CRS that allows uploading files with dangerous extensions (.php, .phar, .jsp, .jspx) by inserting whitespace padding in the filename (e.g. photo. php or shell.jsp ). The affected rules do not normalize whitespace before evaluating the file extension regex, so the dot-extension check fails to match. This issue has been patched in versions 3.3.9 and 4.25.0.
References
| URL | Tags | ||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||||||||||
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| coreruleset | coreruleset |
Version: < 3.3.9 Version: >= 4.0.0-rc1, < 4.25.0 |
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2026-04-18T19:16:54.006Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"url": "http://www.openwall.com/lists/oss-security/2026/03/29/2"
},
{
"url": "http://seclists.org/fulldisclosure/2026/Apr/0"
},
{
"url": "http://www.openwall.com/lists/oss-security/2026/04/18/4"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-33691",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-04-02T17:38:01.007742Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-04-02T17:38:10.247Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "coreruleset",
"vendor": "coreruleset",
"versions": [
{
"status": "affected",
"version": "\u003c 3.3.9"
},
{
"status": "affected",
"version": "\u003e= 4.0.0-rc1, \u003c 4.25.0"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 3.3.9 and 4.25.0, a bypass was identified in OWASP CRS that allows uploading files with dangerous extensions (.php, .phar, .jsp, .jspx) by inserting whitespace padding in the filename (e.g. photo. php or shell.jsp ). The affected rules do not normalize whitespace before evaluating the file extension regex, so the dot-extension check fails to match. This issue has been patched in versions 3.3.9 and 4.25.0."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 6.8,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-178",
"description": "CWE-178: Improper Handling of Case Sensitivity",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-04-02T15:03:52.126Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w"
},
{
"name": "https://github.com/coreruleset/coreruleset/pull/4546",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/coreruleset/coreruleset/pull/4546"
},
{
"name": "https://github.com/coreruleset/coreruleset/pull/4547",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/coreruleset/coreruleset/pull/4547"
},
{
"name": "https://github.com/coreruleset/coreruleset/pull/4548",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/coreruleset/coreruleset/pull/4548"
},
{
"name": "https://github.com/coreruleset/coreruleset/commit/2a8c63512811c5dd74472becebb79a783e68ff02",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/coreruleset/coreruleset/commit/2a8c63512811c5dd74472becebb79a783e68ff02"
},
{
"name": "https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9"
},
{
"name": "https://github.com/coreruleset/coreruleset/releases/tag/v4.25.0",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/coreruleset/coreruleset/releases/tag/v4.25.0"
}
],
"source": {
"advisory": "GHSA-rw5f-9w43-gv2w",
"discovery": "UNKNOWN"
},
"title": "OWASP CRS: Whitespace padding in filenames bypasses file upload extension checks"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-33691",
"datePublished": "2026-04-02T15:03:52.126Z",
"dateReserved": "2026-03-23T16:34:59.932Z",
"dateUpdated": "2026-04-18T19:16:54.006Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"http://www.openwall.com/lists/oss-security/2026/03/29/2\"}, {\"url\": \"http://seclists.org/fulldisclosure/2026/Apr/0\"}, {\"url\": \"http://www.openwall.com/lists/oss-security/2026/04/18/4\"}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2026-04-18T19:16:54.006Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-33691\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-04-02T17:38:01.007742Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-04-02T17:38:04.990Z\"}}], \"cna\": {\"title\": \"OWASP CRS: Whitespace padding in filenames bypasses file upload extension checks\", \"source\": {\"advisory\": \"GHSA-rw5f-9w43-gv2w\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"CHANGED\", \"version\": \"3.1\", \"baseScore\": 6.8, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}], \"affected\": [{\"vendor\": \"coreruleset\", \"product\": \"coreruleset\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 3.3.9\"}, {\"status\": \"affected\", \"version\": \"\u003e= 4.0.0-rc1, \u003c 4.25.0\"}]}], \"references\": [{\"url\": \"https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w\", \"name\": \"https://github.com/coreruleset/coreruleset/security/advisories/GHSA-rw5f-9w43-gv2w\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/coreruleset/coreruleset/pull/4546\", \"name\": \"https://github.com/coreruleset/coreruleset/pull/4546\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/coreruleset/coreruleset/pull/4547\", \"name\": \"https://github.com/coreruleset/coreruleset/pull/4547\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/coreruleset/coreruleset/pull/4548\", \"name\": \"https://github.com/coreruleset/coreruleset/pull/4548\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/coreruleset/coreruleset/commit/2a8c63512811c5dd74472becebb79a783e68ff02\", \"name\": \"https://github.com/coreruleset/coreruleset/commit/2a8c63512811c5dd74472becebb79a783e68ff02\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9\", \"name\": \"https://github.com/coreruleset/coreruleset/releases/tag/v3.3.9\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/coreruleset/coreruleset/releases/tag/v4.25.0\", \"name\": \"https://github.com/coreruleset/coreruleset/releases/tag/v4.25.0\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 3.3.9 and 4.25.0, a bypass was identified in OWASP CRS that allows uploading files with dangerous extensions (.php, .phar, .jsp, .jspx) by inserting whitespace padding in the filename (e.g. photo. php or shell.jsp ). The affected rules do not normalize whitespace before evaluating the file extension regex, so the dot-extension check fails to match. This issue has been patched in versions 3.3.9 and 4.25.0.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-178\", \"description\": \"CWE-178: Improper Handling of Case Sensitivity\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-04-02T15:03:52.126Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-33691\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-18T19:16:54.006Z\", \"dateReserved\": \"2026-03-23T16:34:59.932Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-04-02T15:03:52.126Z\", \"assignerShortName\": \"GitHub_M\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…