FKIE_CVE-2026-49753
Vulnerability from fkie_nvd - Published: 2026-06-02 16:16 - Updated: 2026-07-22 19:10
Severity
Summary
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint Mint allows attacker-controlled HTTP/1 servers to desynchronise response framing on shared connections.
Mint's HTTP/1 Content-Length parser, Mint.HTTP1.Parse.content_length_header/1 in lib/mint/http1/parse.ex, parses the header value with Integer.parse/1, which accepts an optional + or - sign prefix. The length >= 0 guard rejects negatives, but inputs such as +0 or +123 are returned as valid lengths. RFC 7230 specifies Content-Length = 1*DIGIT, with no sign character permitted.
A fronting proxy or load balancer that strictly enforces the grammar will reject or reframe a header like Content-Length: +0, while Mint silently treats it as zero. When Mint reuses the socket (keep-alive, pipelining, or any pooled connection shared across requesters), the parser disagreement is a response-smuggling primitive: the proxy delimits the body one way, Mint another, and bytes from one response get attributed to the next. Where the same Mint connection is shared across trust boundaries, an attacker-controlled upstream can leak bytes into a different consumer's response stream.
This issue affects mint: from 0.1.0 before 1.9.0.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://repo.hex.pm",
"cpes": [
"cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unaffected",
"modules": [
"\u0027Elixir.Mint.HTTP1.Parse\u0027"
],
"packageName": "mint",
"packageURL": "pkg:hex/mint",
"product": "mint",
"programFiles": [
"lib/mint/http1/parse.ex"
],
"programRoutines": [
{
"name": "\u0027Elixir.Mint.HTTP1.Parse\u0027:content_length_header/1"
}
],
"repo": "https://github.com/elixir-mint/mint",
"vendor": "elixir-mint",
"versions": [
{
"lessThan": "1.9.0",
"status": "affected",
"version": "0.1.0",
"versionType": "semver"
}
]
},
{
"collectionURL": "https://github.com",
"cpes": [
"cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unaffected",
"modules": [
"\u0027Elixir.Mint.HTTP1.Parse\u0027"
],
"packageName": "elixir-mint/mint",
"packageURL": "pkg:github/elixir-mint/mint",
"product": "mint",
"programFiles": [
"lib/mint/http1/parse.ex"
],
"programRoutines": [
{
"name": "\u0027Elixir.Mint.HTTP1.Parse\u0027:content_length_header/1"
}
],
"repo": "https://github.com/elixir-mint/mint.git",
"vendor": "elixir-mint",
"versions": [
{
"lessThan": "47e48027480228e4e32a0b4df39db497b4804921",
"status": "affected",
"version": "65e0e86d799a6d3b08e4372fccdd9747535e0dd6",
"versionType": "git"
}
]
}
],
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027) vulnerability in elixir-mint Mint allows attacker-controlled HTTP/1 servers to desynchronise response framing on shared connections.\n\nMint\u0027s HTTP/1 Content-Length parser, Mint.HTTP1.Parse.content_length_header/1 in lib/mint/http1/parse.ex, parses the header value with Integer.parse/1, which accepts an optional + or - sign prefix. The length \u003e= 0 guard rejects negatives, but inputs such as +0 or +123 are returned as valid lengths. RFC 7230 specifies Content-Length = 1*DIGIT, with no sign character permitted.\n\nA fronting proxy or load balancer that strictly enforces the grammar will reject or reframe a header like Content-Length: +0, while Mint silently treats it as zero. When Mint reuses the socket (keep-alive, pipelining, or any pooled connection shared across requesters), the parser disagreement is a response-smuggling primitive: the proxy delimits the body one way, Mint another, and bytes from one response get attributed to the next. Where the same Mint connection is shared across trust boundaries, an attacker-controlled upstream can leak bytes into a different consumer\u0027s response stream.\n\nThis issue affects mint: from 0.1.0 before 1.9.0."
},
{
"lang": "es",
"value": "Una vulnerabilidad de \u0027Interpretaci\u00f3n inconsistente de solicitudes HTTP\u0027 (\u0027Contrabando de Solicitudes/Respuestas HTTP\u0027) en elixir-mint Mint permite a servidores HTTP/1 controlados por el atacante desincronizar el enmarcado de respuestas en conexiones compartidas.\n\nEl analizador Content-Length HTTP/1 de Mint, Mint.HTTP1.Parse.content_length_header/1 en lib/mint/http1/parse.ex, analiza el valor del encabezado con Integer.parse/1, que acepta un prefijo de signo + o - opcional. La guarda length \u003e= 0 rechaza los negativos, pero entradas como +0 o +123 se devuelven como longitudes v\u00e1lidas. RFC 7230 especifica Content-Length = 1DIGIT, sin permitir ning\u00fan car\u00e1cter de signo.\n\nUn proxy frontal o balanceador de carga que aplica estrictamente la gram\u00e1tica rechazar\u00e1 o reenmarcar\u00e1 un encabezado como Content-Length: +0, mientras que Mint lo trata silenciosamente como cero. Cuando Mint reutiliza el socket (keep-alive, pipelining, o cualquier conexi\u00f3n agrupada compartida entre solicitantes), el desacuerdo del analizador es una primitiva de contrabando de respuestas: el proxy delimita el cuerpo de una manera, Mint de otra, y los bytes de una respuesta se atribuyen a la siguiente. Donde la misma conexi\u00f3n de Mint se comparte a trav\u00e9s de l\u00edmites de confianza, un upstream controlado por el atacante puede filtrar bytes en el flujo de respuesta de un consumidor diferente.\n\nEste problema afecta a mint: desde 0.1.0 antes de 1.9.0."
}
],
"id": "CVE-2026-49753",
"lastModified": "2026-07-22T19:10:00.120",
"metrics": {
"cvssMetricV40": [
{
"cvssData": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"availabilityRequirement": "NOT_DEFINED",
"baseScore": 6.3,
"baseSeverity": "MEDIUM",
"confidentialityRequirement": "NOT_DEFINED",
"exploitMaturity": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "LOW",
"subIntegrityImpact": "LOW",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "LOW",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-49753",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-06-02T18:06:41.525477Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-06-02T16:16:44.777",
"references": [
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://cna.erlef.org/cves/CVE-2026-49753.html"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/elixir-mint/mint/commit/47e48027480228e4e32a0b4df39db497b4804921"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/elixir-mint/mint/security/advisories/GHSA-mjqx-c6f6-7rc2"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://osv.dev/vulnerability/EEF-CVE-2026-49753"
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"url": "https://github.com/elixir-mint/mint/security/advisories/GHSA-mjqx-c6f6-7rc2"
}
],
"sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"vulnStatus": "Deferred",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-444"
}
],
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"type": "Secondary"
}
]
}
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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.
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