SB2026051360 - Multiple vulnerabilities in Cpp-httplib

Description

This security bulletin contains information about 2 vulnerabilities.

1) CRLF injection (CVE-ID: CVE-2026-45372)

CWE-ID: CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/U:Green

The vulnerability allows a remote attacker to inject CRLF sequences into stored HTTP header values.

The vulnerability exists due to improper neutralization of CRLF sequences in the server-side parse_header function when parsing percent-encoded header values in incoming requests. A remote attacker can send a specially crafted request with encoded CRLF sequences to inject CRLF sequences into stored HTTP header values.

The issue can lead to inconsistent interpretation of header values by downstream application components, including response handling, logging, and proxying logic.

2) NULL pointer dereference (CVE-ID: CVE-2026-46527)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to undefined behavior from calling front() on an empty std::vector in get_client_ip() when handling HTTP requests with a crafted X-Forwarded-For header under trusted-proxy configuration. A remote attacker can send a specially crafted request to cause a denial of service.

Only deployments that configure a non-empty trusted-proxy list are vulnerable.

Remediation

Install update from vendor's website.

References

• https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m
• https://github.com/yhirose/cpp-httplib/commit/600d220c84853f52011ae4b95fc8518742bcdfac
• https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578g