CVE-2026-112880 CRLF injection in Proxy-Authorization header built from proxy_auth_fun in hackney
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-112880?
CVE-2026-112880 is a low-severity vulnerability in benoitc hackney, published on 26 Oct 2026.
Official description
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in hackney_http_connect in benoitc hackney allows HTTP Request Splitting via the value a proxy_auth_fun callback returns. After a 407 response from an HTTP CONNECT proxy, hackney_http_connect:handle_proxy_auth/11 calls the caller's proxy_auth_fun with the status code and the response headers and writes the returned binary into the Proxy-Authorization line of the CONNECT retry without checking it. A CR, LF or NUL byte in that value adds header lines to the request sent to the proxy.
The value is attacker-influenced when the callback derives it from untrusted data, for example from the proxy's challenge headers. Other caller-supplied values on the CONNECT path, such as the target host and the request headers, were already checked for control bytes.
This issue affects hackney: from 2.0.0 before 4.9.0.
Weakness: CWE-113
Which versions are affected by CVE-2026-112880?
1 open source package ship an affected version, including hackney.
| Package | Affected | Fixed in |
|---|---|---|
hackney Hex | From 2.0.0 | 4.9.0 |
How do I fix CVE-2026-112880?
Upgrade hackney to 4.9.0 or later.
Is CVE-2026-112880 being exploited?
There is no known exploitation of CVE-2026-112880 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-112880, GHSA-5qp8-qrjx-2669.