CVE-2026-49753
HTTP response smuggling in Mint HTTP/1 client via lenient Content-Length parsing
Description
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.
INFO
Published Date :
June 2, 2026, 4:16 p.m.
Last Modified :
July 22, 2026, 7:10 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | MEDIUM | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update Mint to version 1.9.0 or later.
- Apply necessary code changes if any.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-49753.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-49753 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-49753
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-49753 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-49753 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Translated by [email protected]
Jul. 22, 2026
Action Type Old Value New Value Added Translation Title: mint de elixir-mint, Description: Una vulnerabilidad de 'Interpretación inconsistente de solicitudes HTTP' ('Contrabando de Solicitudes/Respuestas HTTP') en elixir-mint Mint permite a servidores HTTP/1 controlados por el atacante desincronizar el enmarcado de respuestas en conexiones compartidas. El 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 >= 0 rechaza los negativos, pero entradas como +0 o +123 se devuelven como longitudes válidas. RFC 7230 especifica Content-Length = 1DIGIT, sin permitir ningún carácter de signo. Un proxy frontal o balanceador de carga que aplica estrictamente la gramática rechazará o reenmarcará un encabezado como Content-Length: +0, mientras que Mint lo trata silenciosamente como cero. Cuando Mint reutiliza el socket (keep-alive, pipelining, o cualquier conexión 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 conexión de Mint se comparte a través de límites de confianza, un upstream controlado por el atacante puede filtrar bytes en el flujo de respuesta de un consumidor diferente. Este problema afecta a mint: desde 0.1.0 antes de 1.9.0. -
CVE Modified by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/elixir-mint/mint', 'vendor': 'elixir-mint', 'modules': ["'Elixir.Mint.HTTP1.Parse'"], 'product': 'mint', 'versions': [{'status': 'affected', 'version': '0.1.0', 'lessThan': '1.9.0', 'versionType': 'semver'}], 'packageURL': 'pkg:hex/mint', 'packageName': 'mint', 'programFiles': ['lib/mint/http1/parse.ex'], 'collectionURL': 'https://repo.hex.pm', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.Mint.HTTP1.Parse':content_length_header/1"}]}, {'cpes': ['cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*'], 'repo': 'https://github.com/elixir-mint/mint.git', 'vendor': 'elixir-mint', 'modules': ["'Elixir.Mint.HTTP1.Parse'"], 'product': 'mint', 'versions': [{'status': 'affected', 'version': '65e0e86d799a6d3b08e4372fccdd9747535e0dd6', 'lessThan': '47e48027480228e4e32a0b4df39db497b4804921', 'versionType': 'git'}], 'packageURL': 'pkg:github/elixir-mint/mint', 'packageName': 'elixir-mint/mint', 'programFiles': ['lib/mint/http1/parse.ex'], 'collectionURL': 'https://github.com', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': "'Elixir.Mint.HTTP1.Parse':content_length_header/1"}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-49753', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-02T18:06:41.525477Z'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 02, 2026
Action Type Old Value New Value Added Reference https://github.com/elixir-mint/mint/security/advisories/GHSA-mjqx-c6f6-7rc2 -
New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Jun. 02, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V4.0 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 Added CWE CWE-444 Added Reference https://cna.erlef.org/cves/CVE-2026-49753.html Added Reference https://github.com/elixir-mint/mint/commit/47e48027480228e4e32a0b4df39db497b4804921 Added Reference https://github.com/elixir-mint/mint/security/advisories/GHSA-mjqx-c6f6-7rc2 Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-49753