HTTP request smuggling via unvalidated method field
Published Jun 2, 2026 · Updated Jun 2, 2026
CRLF injection in Mint before 1.9.0 allows attackers to inject outbound headers and smuggle HTTP/1 requests through a consuming application. The encode_request_line/2 function in lib/mint/http1/request.ex writes the caller-supplied method into the request line without character validation. Exploitation requires an application to pass attacker-controlled method input, after which an additional request can reach an unintended upstream endpoint.
Summary
What happened
CRLF injection in Mint before 1.9.0 allows attackers to inject outbound headers and smuggle HTTP/1 requests through a consuming application. The encode_request_line/2 function in lib/mint/http1/request.ex writes the caller-supplied method into the request line without character validation. Exploitation requires an application to pass attacker-controlled method input, after which an additional request can reach an unintended upstream endpoint.
The record
- CVE
- CVE-2026-48861
- Published
- Jun 2, 2026
- Updated
- Jun 2, 2026
- Vendor
- Elixir Mint
- Product
- Mint
- Classifications
- CWE-93
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 2, 2026CVE publishedPublication date reported by the CVE source.
- Jun 2, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.1.0 <1.9.0
- Affected versionversion=8db1acff30b6a9433762c18b1e1f891b8c1f74f7 <fad091454cbb7449b19edb8e1fee12ca7cf28c3a
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream request-line CRLF injection proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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