@fastify/http-proxy versions before 11.6.2 do not validate proxied HTTP request paths for backslash based dot-segments before forwarding them to the configured upstream. The plain HTTP request handler skips the destination validation that the WebSocket path performs, and the underlying reply-from library only rejects forward-slash traversal, so a request containing backslash dot-segments can escape the boundary set by the prefix and rewritePrefix options. An unauthenticated network attacker can use this to reach upstream paths that were meant to stay hidden behind the proxy, resulting in disclosure of internal endpoints. This is a path traversal issue (CWE-22). Users should upgrade to @fastify/http-proxy 11.6.2 or later.
Metrics
Affected Vendors & Products
References
History
Wed, 09 Sep 2026 19:45:00 +0000
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| First Time appeared |
Fastify fastify\/http-proxy
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| CPEs | cpe:2.3:a:fastify:fastify\/http-proxy:*:*:*:*:*:node.js:*:* | |
| Vendors & Products |
Fastify fastify\/http-proxy
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Thu, 03 Sep 2026 16:00:00 +0000
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Fastify
Fastify fastify-http-proxy |
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| Vendors & Products |
Fastify
Fastify fastify-http-proxy |
Thu, 03 Sep 2026 13:30:00 +0000
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| Metrics |
ssvc
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Thu, 03 Sep 2026 11:00:00 +0000
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| Description | @fastify/http-proxy versions before 11.6.2 do not validate proxied HTTP request paths for backslash based dot-segments before forwarding them to the configured upstream. The plain HTTP request handler skips the destination validation that the WebSocket path performs, and the underlying reply-from library only rejects forward-slash traversal, so a request containing backslash dot-segments can escape the boundary set by the prefix and rewritePrefix options. An unauthenticated network attacker can use this to reach upstream paths that were meant to stay hidden behind the proxy, resulting in disclosure of internal endpoints. This is a path traversal issue (CWE-22). Users should upgrade to @fastify/http-proxy 11.6.2 or later. | |
| Title | @fastify/http-proxy vulnerable to prefix escape via backslash dot-segments | |
| Weaknesses | CWE-22 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: openjs
Published: 2026-09-03T10:51:24.281Z
Updated: 2026-09-03T12:32:56.358Z
Reserved: 2026-09-03T08:15:18.564Z
Link: CVE-2026-85124
Updated: 2026-09-03T12:32:49.123Z
Status : Analyzed
Published: 2026-09-03T13:06:21.773
Modified: 2026-09-09T19:25:40.793
Link: CVE-2026-85124
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