{"cve":"CVE-2026-117518","nvd":{"published":"2026-11-02T11:17:30.660","modified":"2026-11-02T11:17:30.790","status":"Deferred","description":"@fastify/reply-from is a Fastify plugin that forwards requests to an upstream HTTP server. In versions up to and including 12.8.0, the plugin validated proxy paths against forward-slash dot-segments only and then built the target with the WHATWG URL parser, which normalizes a backslash and its percent-encoded form to a forward slash on the http, https, ws, and wss schemes. A path that uses backslash dot-segments therefore bypasses the traversal check and resolves to a different upstream path, so an application that scopes proxying to an upstream prefix, or relies on route guards in front of the forwarding call, can have an unauthenticated request escape the intended prefix and reach other upstream endpoints. The resulting access to unintended upstream resources is primarily a confidentiality impact with limited integrity impact. The issue is fixed in @fastify/reply-from 12.8.1, where the path is normalized and any segment resolving to a single or double dot, along with control characters and ambiguous whitespace, is rejected before the URL is constructed, and users should upgrade to 12.8.1 or later. There is no workaround other than upgrading.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","score":8.2},"cwes":["CWE-22"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-vp2r-3vgv-32g9"],"reference_tags":[{"url":"https://cna.openjsf.org/security-advisories.html","tags":[]},{"url":"https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-vp2r-3vgv-32g9","tags":[]}],"products":[],"affected":[],"source":"nvd","synced_at":"2026-11-02T11:46:51.329548709+00:00"},"epss":null,"kev":null,"exploits":[],"weaknesses":[{"name":"Improper Limitation of a Pathname to a Restricted Directory","common_name":"Path traversal","deprecated":false,"replaced_by":[],"id":"CWE-22"}],"osv":[],"fixed":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program.","Public exploits: links to the Exploit Database (https://www.exploit-db.com, by OffSec; index under GPL-2.0), Rapid7's Metasploit Framework modules (https://github.com/rapid7/metasploit-framework, BSD-3-Clause) and ProjectDiscovery's nuclei templates (https://github.com/projectdiscovery/nuclei-templates, MIT). Only the links, titles and dates are stored; no exploit code is fetched or served.","CWE names and descriptions: MITRE's Common Weakness Enumeration (https://cwe.mitre.org), Copyright © 2006–2026, The MITRE Corporation, under the CWE terms of use (https://cwe.mitre.org/about/termsofuse.html). CWE is a trademark of The MITRE Corporation."]}