---
id: CVE-2026-77341
title: cpp-httplib is a C++ header-only HTTP/HTTPS library
summary: >-
  cpp-httplib is a C++ header-only HTTP/HTTPS library. In version 0.49.0, the
  chunked-response trailer output path writes trailer header names and values
  directly to the socket without validating them, allowing CRLF sequences in a
  trailer …
severity: none
cwe:
  - CWE-93
  - CWE-113
published: '2026-08-28'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:09:13.080'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77341'
references:
  - url: >-
      https://github.com/yhirose/cpp-httplib/commit/568d434e72fc51729d0ad33abffb181e5f7a453d
    label: security-advisories@github.com
  - url: >-
      https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-2r2h-jc8w-w66c
    label: security-advisories@github.com
  - url: >-
      https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-2r2h-jc8w-w66c
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00272
epssPercentile: 0.19857
ingestedAt: '2026-09-09T21:22:45.557Z'
---

## Overview

cpp-httplib is a C++ header-only HTTP/HTTPS library. In version 0.49.0, the chunked-response trailer output path writes trailer header names and values directly to the socket without validating them, allowing CRLF sequences in a trailer field to inject additional headers or split the HTTP response. Unlike every other header-writing path in the library, the trailer-writing code applies none of the field-name and field-value checks that reject carriage return and line feed, so an application that places attacker-influenced data into a chunked response trailer emits attacker-controlled CRLF onto the wire. This enables HTTP response splitting, letting an attacker forge response headers or inject a second response. This issue is fixed in version 0.50.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.