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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-21428 Detail

Description

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.0, the ``write_headers`` function does not check for CR & LF characters in user supplied headers, allowing untrusted header value to escape header lines. This vulnerability allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack. When combined with a server that supports http1.1 pipelining (springboot, python twisted etc), this can be used for server side request forgery (SSRF). Version 0.30.0 fixes this issue.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-BT 7.7 HIGH
Vector:  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

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/yhirose/cpp-httplib/commit/98048a033a532ff22320ce1d11789f8d5710dfcd GitHub, Inc.
https://github.com/yhirose/cpp-httplib/releases/tag/v0.30.0 GitHub, Inc.
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-wpc6-j37r-jcx7 GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-93 Improper Neutralization of CRLF Sequences ('CRLF Injection') GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-21428
NVD Published Date:
01/01/2026
NVD Last Modified:
01/02/2026
Source:
GitHub, Inc.