CVE-2026-33805

Published: Apr 15, 2026 Last Modified: Apr 15, 2026
ExploitDB:
Other exploit source:
Google Dorks:
CRITICAL 9,0
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Confidentiality: N/A
Integrity: N/A
Availability: N/A

Description

AI Translation Available

@fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client's Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests by listing them in the Connection header value. Any header added by the proxy for routing, access control, or security purposes can be selectively removed by a client. @fastify/http-proxy is also affected as it delegates to @fastify/reply-from.

Upgrade to @fastify/reply-from v12.6.2 or @fastify/http-proxy v11.4.4 or later.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0004
Percentile
0,1th
Updated

EPSS Score Trend (Last 2 Days)

644

Improper Neutralization of HTTP Headers for Scripting Syntax

Incomplete
Abstraction: Variant Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Confidentiality Availability
Potential Impacts:
Execute Unauthorized Code Or Commands Read Application Data
Applicable Platforms
Technologies: Web Based, Web Server
Likelihood of Exploit: High
View CWE Details
https://github.com/fastify/fastify-reply-from/security/advi…
https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf7…
https://cna.openjsf.org/security-advisories.html
https://cna.openjsf.org/security-advisories.html
https://github.com/fastify/fastify-reply-from/security/advi…
https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf7…