# CVE-2026-77341

## Summary

- **CVE ID:** CVE-2026-77341
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N)
- **CWE:** CWE-93, CWE-113
- **Published:** Aug 27, 2026
- **Last Modified:** Aug 28, 2026

## Description

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.

## Affected Products

- yhirose — cpp-httplib (>= 0.49.0, < 0.50.0)

## References

- [CNA](https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-2r2h-jc8w-w66c)
- [CNA](https://github.com/yhirose/cpp-httplib/commit/568d434e72fc51729d0ad33abffb181e5f7a453d)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.27%
- **EPSS Percentile:** 19.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._