SB2026082536 - HTTP response splitting in Cpp-httplib

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Main Vulnerability Database SB2026082536

SB2026082536 - HTTP response splitting in Cpp-httplib

Published: August 25, 2026

Security Bulletin ID SB2026082536
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) HTTP response splitting (CVE-ID: CVE-2026-77341)

CWE-ID: CWE-113 - Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to inject arbitrary HTTP response headers.

The vulnerability exists due to improper neutralization of crlf sequences in HTTP trailer headers in the done_with_trailer lambda within write_content_chunked() when writing chunked response trailers containing attacker-controlled input. A remote attacker can supply crafted input containing crlf characters that is reflected into trailer fields to inject arbitrary HTTP response headers.

Exploitation requires an application to reflect attacker-controlled data into chunked response trailers via DataSink::done_with_trailer().


Remediation

Install update from vendor's website.

References