← Vulnerability feed

Vulnerability record · CVE-2026-15631 · published 18 July 2026

CVE-2026-15631: Fastify\/http-proxy path traversal vulnerability

Fastify · Fastify\/Http Proxy

Impact: @fastify/http-proxy versions from 9.4.0 up to and including 11.5.0 fail to validate the resolved WebSocket destination path against the configured rewrite prefix. The WebSocket routing path in WebSocketProxy.findUpstream resolves the destination via the WHATWG URL constructor, which collapses dot segments, so a crafted upgrade request with path traversal sequences can escape the rewrite prefix and reach upstream endpoints that were not meant to be exposed by the proxy. This is a variant of CVE-2021-21322 in a code path that never went through the HTTP fix in fastify/reply-from. Exploitation requires a non-normalizing WebSocket client, since browsers and the ws package normalize the request path before sending, but raw HTTP clients or downstream proxies that forward the request target unchanged make the attack reachable in production topologies. Patches: upgrade to @fastify/http-proxy 11.6.0. Workarounds: none.

10.0 CVSS 3.1 Critical EPSS 0.50% · top 59.5% CWE-22 · Path traversal
10.0CVSS 3.1 base score
0.50%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
28 Jul 2026Last modified by NVD

Description

Impact: @fastify/http-proxy versions from 9.4.0 up to and including 11.5.0 fail to validate the resolved WebSocket destination path against the configured rewrite prefix. The WebSocket routing path in WebSocketProxy.findUpstream resolves the destination via the WHATWG URL constructor, which collapses dot segments, so a crafted upgrade request with path traversal sequences can escape the rewrite prefix and reach upstream endpoints that were not meant to be exposed by the proxy. This is a variant of CVE-2021-21322 in a code path that never went through the HTTP fix in fastify/reply-from. Exploitation requires a non-normalizing WebSocket client, since browsers and the ws package normalize the request path before sending, but raw HTTP clients or downstream proxies that forward the request target unchanged make the attack reachable in production topologies. Patches: upgrade to @fastify/http-proxy 11.6.0. Workarounds: none.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cna.openjsf.org/security-advisories.html Vendor Advisory
https://github.com/fastify/fastify-http-proxy/security/advisories/GHSA-7hrw-592w-9wh2 Vendor Advisory

Track CVE-2026-15631 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2026-16117Fastify\/http-proxy improper input validation vulnerabilityImpact: @fastify/http-proxy versions up to and including 11.5.0 fail to rewrite the request prefix when the prefix segment is URL-encoded. Fastify's …EPSS 0.44%9.0CVE-2026-33805Fastify\/http-proxy http request smuggling vulnerability@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 …EPSS 0.56%7.5CVE-2026-85124Fastify\/http-proxy path traversal vulnerability@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 …EPSS 0.74%9.8CVE-2026-93616Checkpoint multi-domain security management path traversal vulnerabilityA directory traversal and file upload vulnerability allows an unauthenticated attacker to upload and execute arbitrary scripts on Check Point Managem…KEVEPSS 20%10.0CVE-2026-85706GitLab CE/EE repository commits API path traversal allows unauthenticated file readGitLab CE/EE contains improper path confinement and missing authentication enforcement in the repository commits API, allowing an unauthenticated use…KEVEPSS 91%analysed5.3CVE-2026-66384JFrog Artifactory path traversal in Docker cache pathAn authenticated user can write data outside the intended Docker cache path under specific remote-repository conditions in JFrog Artifactory. The fla…KEVEPSS 0.66%analysed9.8CVE-2026-59310VMware vCenter Syslog server path traversal leads to RCEVMware vCenter's Syslog server is affected by a directory traversal flaw (CWE-22) that allows a remote, unauthenticated attacker to execute arbitrary…KEVEPSS 2.6%analysed10.0CVE-2026-48282Adobe ColdFusion path traversal leads to remote code executionColdFusion versions 2025.9, 2023.20 and earlier contain a path traversal flaw (CWE-22) that allows an unauthenticated remote attacker to reach files …KEVEPSS 42%analysed

Source: NIST National Vulnerability Database (record CVE-2026-15631), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.