CVE-2018-12542

Eclipse Vert.x does not properly neutralize '' (forward slashes) sequences that can resolve to an external location

9.8 CriticalPublic exploitFix available

In version from 3.0.0 to 3.5.3 of Eclipse Vert.x, the StaticHandler uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize '' (forward slashes) sequences that can resolve to a location that is outside of that directory when running on Windows Operating Systems.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

2.22%Down 6.5 points since Apr 14, 2021

What each source reports

NVD Score used 9.8

Record: CVE-2018-12542
CVSS 3.0: 9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0: 7.5 HighAV:N/AC:L/Au:N/C:P/I:P/A:P
Weakness: CWE-22
Updated: 2026-11-02

CVE List No score

Record: CVE-2018-12542
Updated: 2026-11-02

EUVDEUVD-2018-0608 No score

Record: EUVD-2018-0608
Updated: 2026-11-03

GitHub AdvisoriesGHSA-h39x-m55c-v55h 9.8

Eclipse Vert.x does not properly neutralize '' (forward slashes) sequences that can resolve to an external location

Record: GHSA-h39x-m55c-v55h
CVSS 3.0: 9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-22
Updated: 2026-11-02

OSV 9.8

Record: CVE-2018-12542
CVSS 3.0: 9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVGHSA-h39x-m55c-v55h 9.8

Eclipse Vert.x does not properly neutralize '' (forward slashes) sequences that can resolve to an external location

Record: GHSA-h39x-m55c-v55h
CVSS 3.0: 9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-22
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`io.vertx:vertx-web` Maven	3.0.0 up to 3.5.4	3.5.4
`io.vertx:vertx-web` Maven	3.0.0 up to 3.5.4, plus listed versions 3.1.03.2.03.2.13.3.03.3.0.CR1 Show 17 moreShow less 3.3.0.CR23.3.13.3.23.3.33.4.03.4.0.Beta13.4.13.4.23.5.03.5.0.Beta13.5.13.5.23.5.2.CR13.5.2.CR23.5.2.CR33.5.33.5.3.CR1	3.5.4

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
Source	Link	Date
PoC in GitHub	shoucheng3/vert-x3__vertx-web_CVE-2018-12542_3-5-3-CR1	2025-08-16

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, products	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV, PoC in GitHub

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-12542 is a critical vulnerability (CVSS 9.8) in Eclipse Vert.x, published October 10, 2018. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 2.22%, the 82nd percentile. Fixed in io.vertx:vertx-web 3.5.4.