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1 vulnerability by @fastify/reply-from

CVE-2026-33805 (GCVE-0-2026-33805)

Vulnerability from cvelistv5 – Published: 2026-04-15 10:13 – Updated: 2026-04-15 13:08
VLAI?
Title
@fastify/reply-from vulnerable to connection header abuse enabling stripping of proxy-added headers
Summary
@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.
Severity ?
9 (Critical)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:L/SI:H/SA:N
CWE
  • CWE-644 - Improper Neutralization of HTTP Headers for Scripting Syntax
Assigner
References
Impacted products
Vendor Product Version
@fastify/reply-from @fastify/reply-from Affected: 0 , < 12.6.2 (semver)
Unaffected: 12.6.2 (semver)
Create a notification for this product.
    @fastify/reply-from @fastify/http-proxy Affected: 0 , < 11.4.4 (semver)
Unaffected: 11.4.4 (semver)
Create a notification for this product.
Credits
FredKSchott mcollina UlisesGascon climba03003
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