HTTP response splitting in Cpp-httplib - CVE-2026-103930
Published: October 2, 2026
Vulnerability identifier: #VU153191
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-103930
CWE-ID: CWE-113
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to inject or reshape outbound HTTP request metadata.
The vulnerability exists due to improper neutralization of CRLF sequences in Client::open_stream when serializing an attacker-controlled path into an outbound HTTP/1.1 request line. A remote attacker can supply a crafted path containing CRLF sequences through an embedding application to inject or reshape outbound HTTP request metadata.
Exploitation requires an application to forward attacker-controlled paths and a backend or intermediary to interpret the CRLF-delimited bytes as meaningful request metadata.
Affected software
Cpp-httplib
How to mitigate CVE-2026-103930
Install security update from vendor's website.
Cpp-httplib - update to 0.51.0