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Public proof of concept

CVE-2026-103387

garycourt uri-js Mailto Header mailto.ts URI.parse uncaught exception

A public proof of concept exists; no exploitation attested.

  • Published2026-09-30
  • WeaknessCWE-248

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A weakness has been identified in garycourt uri-js up to 4.4.1. This affects the function URI.parse of the file src/schemes/mailto.ts of the component Mailto Header Handler. This manipulation of the argument to causes uncaught exception. The attack may be initiated remotely. The exploit has been made available to the public and could be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Timeline

dates in UTC
  1. 2026-09-3020:17CVE publishedNVD

Versions per branch

Products declared by the CNA1 product

As VulDB, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • garycourt uri-js
    Affected
    • = 4.4.0no fix stated
    • = 4.4.1no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-09-30

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • js-jqueryAzure Linux:3all versions · no fixed version listed
  • node-uri-jsUbuntu:26.10all versions · no fixed version listed
  • node-uri-jsUbuntu:26.04:LTSall versions · no fixed version listed
  • node-uri-jsUbuntu:24.04:LTSall versions · no fixed version listed
  • node-uri-jsUbuntu:22.04:LTSall versions · no fixed version listed
  • node-uri-jsUbuntu:20.04:LTSall versions · no fixed version listed
  • node-uri-jsDebian:14all versions · no fixed version listed
  • node-uri-jsDebian:13all versions · no fixed version listed

1 more package range on OSV.dev

Vendor advisories

  • CVE-2026-103387 Red Hat Product Security

    uri-js: uri-js: Denial of Service via crafted mailto URI

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2026-09-30
  • CNACVSS 4.02.1known since 2026-10-23
  • NVDCVSS 3.14.3read 2026-10-23
  • CNACVSS 2.05known since 2026-10-23
  • NVDweakness (CWE)CWE-248read 2026-10-23
  • FIRST EPSSEPSS score0.3 %2026-11-09
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
CVSS 4.0 vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-09-30
Last Modified
2026-10-01
NVD status
Deferred
GitHub Advisory
GHSA-cw9r-3wqp-32hm

Frequently asked questions

What is CVE-2026-103387?

A weakness has been identified in garycourt uri-js up to 4.4.1. This affects the function URI.parse of the file src/schemes/mailto.ts of the component Mailto Header Handler. This manipulation of the argument to causes uncaught exception. The attack may be initiated remotely. The exploit has been made available to the public and could be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Is CVE-2026-103387 actively exploited?

A proof-of-concept exploit exists for CVE-2026-103387, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-103387?

CVE-2026-103387 has a CVSS v3 base score of 4.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L.

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