CVE-2026-103387

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.31% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 24.6% of scored records. A rank, not a probability.

NVD base score

2.1 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS 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

NVD analysis status

Deferred. NVD last modified this record on 2026-10-01.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-09-30 19:45Z28 DAYS AGO

Last updated

2026-09-30 19:55Z28 DAYS AGO

Reserved

2026-09-30

Assigning CNA

VulDB

Record state

PUBLISHED

Severity

Medium (CVSS 5.3)

CNA CVSS 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

Weaknesses

• CWE-248Uncaught ExceptionBase

Data version

5.2

Document digest

c5fc0faec5fe5f60e63a2374001b0ce3ac80db918873551c786610ae9d02a369

• vuldb.comVDB-412124 | garycourt uri-js Mailto Header mailto.ts URI.parse uncaught exceptionhttps://vuldb.com/vuln/412124vdb-entrytechnical-description
• vuldb.comVDB-412124 | CTI Indicators (IOB, IOC, IOA)https://vuldb.com/vuln/412124/ctisignaturepermissions-required
• vuldb.comCVE-2026-103387 | CVE Analysis and Reporthttps://vuldb.com/cve/CVE-2026-103387third-party-advisory
• vuldb.comSubmit #956810 | garycourt uri-js 4.4.1 Missing Undefined Check on Mailto URI 'to' Header Parserhttps://vuldb.com/submit/956810third-party-advisory
• github.comhttps://github.com/garycourt/uri-js/issues/103exploitissue-tracking
• github.comhttps://github.com/garycourt/uri-js/product