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NVD / CVE Program· CNA openjs

CVE-2026-75899: fast-uri vulnerable to server-side request forgery via repeated hostname percent-decoding

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.22% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: fast-uri fast-uri 2.4.5, 3.1.6, 4.1.3.

Low priority for now. Upgrade to fast-uri fast-uri 2.4.5, 3.1.6, 4.1.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Aug 24, 2026
Updated
Oct 14, 2026
EPSS
0.2% · 12th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · openjs
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-75899

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
openjsffast-uri

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • openjsf fast-uri2.4.1 and later · before 2.4.5
  • openjsf fast-uri3.1.2 and later · before 3.1.6
  • openjsf fast-uri4.0.0 and later · before 4.1.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (openjs). Independent of NVD's CPE analysis and usually ahead of it.

  • fast-uri fast-uri

    • 2.4.5, 3.1.6, 4.1.3not affected
    • 2.4.1 and later · before 2.4.5affected · semver
    • 3.1.2 and later · before 3.1.6affected · semver
    • 4.0.0 and later · before 4.1.3affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10cockpit-image-builderbefore 94.4-1.el10_294.4-1.el10_2
Debian:13node-ajvfrom 0—
Debian:14node-ajvbefore 8.20.0~ds+~cs7.1.4-18.20.0~ds+~cs7.1.4-1
npmfast-urifrom 2.4.1 · before 2.4.52.4.5
npmfast-urifrom 3.1.2 · before 3.1.63.1.6
npmfast-urifrom 4.0.0 · before 4.1.34.1.3
Red Hat:enterprise_linux:10.2cockpit-image-builderbefore 0:94.4-1.el10_20:94.4-1.el10_2
Red Hat:hummingbird:1grafana12.4before 0:12.4.9-0.4.hum10:12.4.9-0.4.hum1
Red Hat:hummingbird:1grafana13.1before 0:13.1.3-0.3.hum10:13.1.3-0.3.hum1
Red Hat:hummingbird:1grafana13.2before 0:13.2.0-0.1.2.hum10:13.2.0-0.1.2.hum1
Rocky Linux:10cockpit-image-builderbefore 0:94.4-1.el10_20:94.4-1.el10_2

Same product

openjsf: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-84394fast-uri vulnerable to host confusion via an unclosed bracket in the URI authority
    30Monitor
  • CVE-2026-84292fast-uri vulnerable to authority injection via an unvalidated port in serialize
    30Monitor
  • CVE-2026-76172fast-uri vulnerable to host confusion via percent-encoded scheme normalization
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-16221Jul 19, 2026 · fast-uri vulnerable to host confusion via literal backslash authority delimiter
    30Monitor
  • ← EarlierCVE-2026-18446Jul 31, 2026 · fast-uri vulnerable to host confusion via backslash authority introducer
    30Monitor
  • Later →CVE-2026-75931Aug 24, 2026 · fast-uri vulnerable to host confusion via skipped IDN canonicalization on scheme-relative references
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
fast-uri fast-uri2.4.5Vendor (CNA)
fast-uri fast-uri3.1.6Vendor (CNA)
fast-uri fast-uri4.1.3Vendor (CNA)
almalinux:cockpit-image-builder94.4-1.el10_2 · AlmaLinux:10Package registry (OSV)
debian:node-ajv8.20.0~ds+~cs7.1.4-1 · Debian:14Package registry (OSV)
npm:fast-uri2.4.5Package registry (OSV)
npm:fast-uri3.1.6Package registry (OSV)
npm:fast-uri4.1.3Package registry (OSV)
red hat:cockpit-image-builder0:94.4-1.el10_2 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:grafana12.40:12.4.9-0.4.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:grafana13.10:13.1.3-0.3.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:grafana13.20:13.2.0-0.1.2.hum1 · Red Hat:hummingbird:1Package registry (OSV)
rocky linux:cockpit-image-builder0:94.4-1.el10_2 · Rocky Linux:10Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-174 · Double Decoding of the Same Data

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records