@fastify/http-proxy vulnerable to prefix escape via percent-encoded backslash dot-segments
CVSS score
5.9
EPSS probability
—
Risk score
0.6
Published
2 h ago
Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.
Impact on My Inventory
Only the personal products you have added to your account are assessed; an organisation's inventory does not appear here.
Checking session…
Vulnerability description
DayBreach AI Explanation
Verified against sourcesSources read
1
Source agreement
Tam uyum
Evidence confidence
%55
Short explanation
@fastify/http-proxy versions 11.6.0 through 11.6.2 are vulnerable to prefix escape via percent-encoded backslash and dot-segments, bypassing destination validation.
Unauthenticated remote attackers can retrieve upstream resources outside the intended prefix, resulting in confidentiality impact.
What should be done?
- Upgrade to @fastify/http-proxy version 11.6.3 or later
- Follow the vendor advisory
Chain of evidence and sources
@fastify/http-proxy sürümleri 11.6.0 ile 11.6.2 arasında önek kaçırma zafiyeti bulunmaktadır.
Saldırganlar bu açıklığı kullanarak önek dışındaki üst akış kaynaklarına erişebilir.
Show the technical text from the sources
@fastify/http-proxy is a Fastify plugin that proxies HTTP requests to an upstream server under a configured prefix. In versions 11.6.0 through 11.6.2, the destination validation normalizes literal backslashes before it percent-decodes the request path, so a path that encodes its backslashes and dot-segments survives the dot-segment check and is only turned into backslash and double-dot sequences after that check has passed. When the upstream resolves on a platform that treats a backslash as a path separator, the forwarded request walks out of the configured proxy prefix and reaches a sibling location on the upstream. An unauthenticated remote attacker can use this to retrieve upstream resources outside the intended prefix, so the impact is confidentiality only, and exploitation depends on the upstream's path handling. The issue is fixed in @fastify/http-proxy 11.6.3, and users should upgrade to 11.6.3 or later. This is a follow-up to the earlier prefix-escape fix, which did not account for the encoded-backslash form.
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE: CWE-22
This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-120214 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | @fastify/http-proxy | @fastify/http-proxy | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 5.9 | CVSS V31 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N | NVD |
| 5.9 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N | CVE CNA |
Patch and Remediation Guide
Solution & Remediation Advisory
İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.
Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-120214 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-120214 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
CVSS Vector Radar Chart
5.9 / 10Vulnerability Scoring Details
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:NYama durumu bilinmiyor
Weakness Type (CWE & CAPEC)
Similar Vulnerabilities
Get this vulnerability through the API
Affected products, version ranges, exploitation status and patch information in a single request, with a free key.
curl -H "x-api-key: $DAYBREACH_API_KEY" \ "https://api.daybreach.dev/api/v1/intel/cves/CVE-2026-120214"