FKIE_CVE-2021-31920
Vulnerability from fkie_nvd - Published: 2021-05-27 05:15 - Updated: 2026-06-17 03:52
Severity
Summary
Istio before 1.8.6 and 1.9.x before 1.9.5 has a remotely exploitable vulnerability where an HTTP request path with multiple slashes or escaped slash characters (%2F or %5C) could potentially bypass an Istio authorization policy when path based authorization rules are used.
References
| URL | Tags | ||
|---|---|---|---|
| cve@mitre.org | https://istio.io/latest/news/security/istio-security-2021-005/ | Exploit, Vendor Advisory | |
| af854a3a-2127-422b-91ae-364da2661108 | https://istio.io/latest/news/security/istio-security-2021-005/ | Exploit, Vendor Advisory |
{
"affected": [
{
"affectedData": [
{
"product": "n/a",
"vendor": "n/a",
"versions": [
{
"status": "affected",
"version": "n/a"
}
]
}
],
"source": "cve@mitre.org"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:istio:istio:*:*:*:*:*:*:*:*",
"matchCriteriaId": "CD72BDF7-907A-407F-94BF-ACDB1F8FFAD1",
"versionEndExcluding": "1.8.6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:istio:istio:*:*:*:*:*:*:*:*",
"matchCriteriaId": "EF73EA19-5803-4F37-A250-1C8597A17FA1",
"versionEndExcluding": "1.9.5",
"versionStartIncluding": "1.9.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Istio before 1.8.6 and 1.9.x before 1.9.5 has a remotely exploitable vulnerability where an HTTP request path with multiple slashes or escaped slash characters (%2F or %5C) could potentially bypass an Istio authorization policy when path based authorization rules are used."
},
{
"lang": "es",
"value": "Istio versiones anteriores a 1.8.6 y versiones 1.9.x anteriores a 1.9.5 presenta una vulnerabilidad explotable de forma remota en la que una ruta de petici\u00f3n HTTP con m\u00faltiples barras o caracteres de barra de escape (%2F o %5C) podr\u00eda omitir potencialmente una pol\u00edtica de autorizaci\u00f3n de Istio cuando las reglas de autorizaci\u00f3n basadas en la ruta son usadas"
}
],
"id": "CVE-2021-31920",
"lastModified": "2026-06-17T03:52:29.560",
"metrics": {
"cvssMetricV2": [
{
"acInsufInfo": false,
"baseSeverity": "MEDIUM",
"cvssData": {
"accessComplexity": "LOW",
"accessVector": "NETWORK",
"authentication": "SINGLE",
"availabilityImpact": "NONE",
"baseScore": 4.0,
"confidentialityImpact": "PARTIAL",
"integrityImpact": "NONE",
"vectorString": "AV:N/AC:L/Au:S/C:P/I:N/A:N",
"version": "2.0"
},
"exploitabilityScore": 8.0,
"impactScore": 2.9,
"obtainAllPrivilege": false,
"obtainOtherPrivilege": false,
"obtainUserPrivilege": false,
"source": "nvd@nist.gov",
"type": "Primary",
"userInteractionRequired": false
}
],
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 6.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2021-05-27T05:15:06.880",
"references": [
{
"source": "cve@mitre.org",
"tags": [
"Exploit",
"Vendor Advisory"
],
"url": "https://istio.io/latest/news/security/istio-security-2021-005/"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
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"Vendor Advisory"
],
"url": "https://istio.io/latest/news/security/istio-security-2021-005/"
}
],
"sourceIdentifier": "cve@mitre.org",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-706"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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