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CVE-2026-75899Suited to automated attack · CISA

fast-uri vulnerable to server-side request forgery via repeated hostname percent-decoding

CVSS score

7.5

EPSS probability

%0.2

Risk score

0.0

Published

1 mo ago

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-75899 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

fast-uri is a URI parser for Node.js. It decodes percent escapes in a hostname during parsing and then decodes the parsed hostname a second time during authority recomposition, so a single call to normalize or resolve can turn nested percent-encoded input into a different network destination such as a loopback hostname or address. For example, a doubly encoded host that spells out a loopback name decodes to that live host in one operation, which contradicts RFC 3986 section 2.4 that an implementation must not decode the same string more than once. An application that normalizes or resolves an untrusted HTTP-family URI before outbound routing, redirect validation, or a host-policy check can receive a destination different from the one the original encoded host represented, giving a server-side request forgery and host-policy bypass primitive. This is an incomplete-fix variant of CVE-2026-6322. The affected versions are 2.4.1 up to but not including 2.4.5, 3.1.2 up to but not including 3.1.6, and 4.0.0 up to but not including 4.1.3. The issue is fixed in 2.4.5, 3.1.6, and 4.1.3, which normalize percent escapes once and preserve encoded percent signs. Users should upgrade to a patched version.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-75899 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1fast-urifast-uri View
2openjsffast-uri View
3openjsffast-uri View
4openjsffast-uri View
5npmfast-uri View
6npmfast-uri View
7npmfast-uri View
8npmfast-uri View
9npmfast-uri View
10npmfast-uri View
Total affected vendors: 3|Products: 10

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

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.

SCOREVERSIONSEVERITYVECTORSOURCE
7.5CVSS V3_1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NCVE CNA
7.5CVSS V31HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NNVD
7.5CVSS 3.x—Vector not publishedGitHub Advisory
0.0CVSS 4.0—Vector not publishedGitHub Advisory

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

3 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

osvfast-uri2.4.5

OSV düzeltilmiş sürüm: 2.4.5

osvfast-uri3.1.6

OSV düzeltilmiş sürüm: 3.1.6

osvfast-uri4.1.3

OSV düzeltilmiş sürüm: 4.1.3

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

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-2026-75899 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-2026-75899 weaknesses.

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

CVSS Vector Radar Chart

7.5 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityNone

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)None

Yama doğrulandı

3 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

F
fast-uri logo
fast-uri
O
openjsf logo
openjsf
N
npm logo
npm

Weakness Type (CWE & CAPEC)

Similar Vulnerabilities

Get this vulnerability through the API

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  "https://api.enginteksut.com.tr/api/v1/intel/cves/CVE-2026-75899"