CVE-2026-40912 (GCVE-0-2026-40912)
Vulnerability from cvelistv5
Published
2026-04-30 20:38
Modified
2026-05-01 14:54
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-706 - Use of Incorrectly-Resolved Name or Reference
Summary
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a high severity authentication bypass vulnerability in Traefik's StripPrefixRegex middleware when used in combination with ForwardAuth, BasicAuth, or DigestAuth. The middleware matches the regex against the decoded URL path but uses the resulting byte length to slice the percent-encoded raw path. When a dot (or multiple dots) appears in the prefix portion of the URL, the raw path after stripping becomes a dot-segment (e.g. /./admin/secret). ForwardAuth receives this dot-segment path in X-Forwarded-Uri, which does not match the protected path patterns and therefore allows the request through. The backend then normalizes the dot-segment to the real path per RFC 3986 and serves the protected content An unauthenticated attacker can exploit this against any backend that performs dot-segment normalization. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.
References
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Impacted products
{
"containers": {
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{
"metrics": [
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"other": {
"content": {
"id": "CVE-2026-40912",
"options": [
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"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-01T14:53:15.470528Z",
"version": "2.0.3"
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"type": "ssvc"
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"providerMetadata": {
"dateUpdated": "2026-05-01T14:54:06.078Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
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"cna": {
"affected": [
{
"product": "traefik",
"vendor": "traefik",
"versions": [
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"status": "affected",
"version": "\u003c 2.11.43"
},
{
"status": "affected",
"version": "\u003e= 3.0.0-beta1, \u003c 3.6.14"
},
{
"status": "affected",
"version": "\u003e= 3.7.0-ea.1, \u003c 3.7.0-rc.2"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a high severity authentication bypass vulnerability in Traefik\u0027s StripPrefixRegex middleware when used in combination with ForwardAuth, BasicAuth, or DigestAuth. The middleware matches the regex against the decoded URL path but uses the resulting byte length to slice the percent-encoded raw path. When a dot (or multiple dots) appears in the prefix portion of the URL, the raw path after stripping becomes a dot-segment (e.g. /./admin/secret). ForwardAuth receives this dot-segment path in X-Forwarded-Uri, which does not match the protected path patterns and therefore allows the request through. The backend then normalizes the dot-segment to the real path per RFC 3986 and serves the protected content An unauthenticated attacker can exploit this against any backend that performs dot-segment normalization. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2."
}
],
"metrics": [
{
"cvssV4_0": {
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"privilegesRequired": "NONE",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "HIGH",
"subIntegrityImpact": "LOW",
"userInteraction": "NONE",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE"
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],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-706",
"description": "CWE-706: Use of Incorrectly-Resolved Name or Reference",
"lang": "en",
"type": "CWE"
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],
"providerMetadata": {
"dateUpdated": "2026-04-30T20:38:21.969Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/traefik/traefik/security/advisories/GHSA-6jwx-7vp4-9847",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/traefik/traefik/security/advisories/GHSA-6jwx-7vp4-9847"
},
{
"name": "https://github.com/traefik/traefik/releases/tag/v2.11.43",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/traefik/traefik/releases/tag/v2.11.43"
},
{
"name": "https://github.com/traefik/traefik/releases/tag/v3.6.14",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/traefik/traefik/releases/tag/v3.6.14"
},
{
"name": "https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2"
}
],
"source": {
"advisory": "GHSA-6jwx-7vp4-9847",
"discovery": "UNKNOWN"
},
"title": "Traefik: StripPrefixRegex auth bypass via Path/RawPath desync"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-40912",
"datePublished": "2026-04-30T20:38:21.969Z",
"dateReserved": "2026-04-15T16:37:22.768Z",
"dateUpdated": "2026-05-01T14:54:06.078Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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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.
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