SB2026072013 - HTTP headers manipulatin in Fastify http-proxy and reply-from
Published: July 20, 2026
Security Bulletin ID
SB2026072013
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Input validation error (CVE-ID: CVE-2026-33805)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 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/E:U/U:Green
The vulnerability allows a remote attacker to strip proxy-added headers.
The vulnerability exists due to improper input validation in the connection header handling logic of @fastify/reply-from and @fastify/http-proxy when processing requests containing a crafted Connection header. A remote attacker can send a specially crafted request to strip proxy-added headers.
Remediation
Install update from vendor's website.