Vulnerability · CVE-2026-49753
Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint Mint allows attacker-controlled HTTP/1 servers to desynch…
Published Jun 2, 2026 · corrected/updated Jul 22, 2026 · evidence confidence medium
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.
Grounded briefings
Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.
Executive
CVE-2026-49753 is a medium public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.
System administrator
Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected version ranges have not been ingested yet. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.
Security analyst
Signals on file: CVSS 6.3. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-444. Sources contributing to this record: nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.
Exploitation and remediation
Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Jun 2, 2026 · NIST NVD
Detected
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 - s
Jul 22, 2026 · NIST NVD
Updated
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 - s
Sources
- NIST NVDVulnerability recordCVE-2026-49753
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_len
nvd.nist.gov