CVE-2026-47075
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk39th percentile - higher than 39% of all known CVEs
Summary
hackney before version 4.0.1 does not percent-encode CR (\r) and LF (\n) characters in the URL query component, enabling HTTP Request Splitting. An attacker controlling the URL can inject raw CRLF sequences into the query string, allowing arbitrary HTTP headers or request splitting.
Risk Assessment
The risk includes HTTP request manipulation, header injection, session hijacking, or cache poisoning attacks, potentially compromising communication integrity.
Recommendation
Upgrade hackney to version 4.0.1 or later, which properly percent-encodes CR and LF characters in URLs.
Other vulnerabilities in hackney
See all- CVE-2026-47077High
A vulnerability in the hackney library (versions 2.0.0 through 4.0.1) allows a Flooding attack due to missing size limits on the HTTP/3 response buffer. A malicious server can send small chunks, resetting the timeout, leading to unbounded memory growth and exhaustion of the BEAM process heap.
- CVE-2026-47076Medium
The hackney library for Erlang/OTP versions 0.13.0 through 4.0.1 contains a Server-Side Request Forgery (SSRF) vulnerability due to an interpretation conflict. The URL normalizer decodes the host after validation, allowing bypass of allowlists and access to internal IP addresses (e.g., 127.0.0.1, 169.254.169.254).
- CVE-2026-47073High
A vulnerability in the hackney library (versions 2.0.0 through 4.0.1) allows memory exhaustion by an attacker-controlled WebSocket server. The WebSocket client does not limit buffer sizes in three code paths, enabling a Flooding attack.
- CVE-2026-47072High
CRLF Injection vulnerability in the hackney library allows an attacker to inject arbitrary HTTP headers into a WebSocket request. Lack of CRLF and NUL filtering at four injection points enables request manipulation, potentially leading to credential spoofing, cache poisoning, or request smuggling via proxies.
- CVE-2026-47071High
The hackney library versions 0.10.0 up to (but not including) 4.0.1 contains an uncontrolled resource consumption vulnerability in the SOCKS5 transport. After SOCKS5 negotiation, the connection is upgraded to TLS with an infinite timeout, allowing a malicious proxy to block the process indefinitely.
- CVE-2026-47070Medium
The hackney library versions 3.1.1 before 4.0.1 is vulnerable to sensitive data exposure. The HTTP/3 module (hackney_h3.erl) does not perform cross-origin checks on redirects, causing authorization headers and cookies to be sent to foreign hosts.
- CVE-2026-47069Medium
A CRLF Injection vulnerability was found in the hackney library (versions from 0.9.0 before 4.0.1) in the hackney_cookie:setcookie/3 function. An attacker controlling the domain or path option can inject a CRLF sequence and arbitrary Set-Cookie headers, leading to HTTP Response Splitting.
- CVE-2026-47067High
The hackney library versions 2.0.0 up to (but not including) 4.0.1 contains a vulnerability that exhausts the BEAM atom table. The URL parser converts unrecognized URL schemes to atoms via binary_to_atom/2, which are never garbage-collected. An attacker can supply many URLs with unique schemes, exceeding the atom table limit and crashing the entire BEAM VM.
- CVE-2026-47066High
The hackney library versions 2.0.0-beta.1 up to (but not including) 4.0.1 contains an infinite loop vulnerability in the Alt-Svc header parser. The parse_token/2 function does not guarantee forward progress for certain bytes, leading to a recursive loop consuming 100% CPU. An Alt-Svc: ! header is sufficient to trigger the vulnerability.
Original NVD description (English source)
Improper Neutralization of CRLF Sequences vulnerability in benoitc hackney allows HTTP Request Splitting. hackney does not percent-encode carriage return (\r) or line feed (\n) characters in the URL query component before constructing the HTTP/1.1 request target. Characters outside the grammar defined in RFC 3986 Section 3.4 must be percent-encoded, but hackney_url:make_url/3 passes the query binary directly without validation or escaping. An attacker who can control all or part of a URL passed to hackney can inject raw CRLF sequences into the query string, which are then sent as HTTP line breaks in the request target. This enables injection of arbitrary HTTP headers or splitting of the HTTP request. This issue affects hackney: from 0.13.1 before 4.0.1.