Cyber Resilience

CVE-2026-14631

Webpack.Js Webpack-Dev-Server ≤ 5.2.6

Published
03 July 2026
Modified
07 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS Score 0.0040 34th percentile
Risk Priority 44 floored blend · peak EPSS

Summary

CVE-2026-14631 is a medium-severity Improper Input Validation (CWE-20) vulnerability in Webpack.Js Webpack-Dev-Server. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 34th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A05:2025 InjectionA10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

webpack-dev-server versions 5.2.5 and earlier terminate the whole Node.js process when an unauthenticated peer sends either a normal HTTP request with a malformed Host header or a WebSocket upgrade to the default /ws endpoint with a malformed Origin header. The…

more

malformed value causes an uncaught exception in the host-validation path and crashes the dev server. Impact is limited to availability of the development server, no data disclosure, no code execution. Patches: upgrade to webpack-dev-server 5.2.6. Workarounds: keep the dev server bound to localhost (the default) and do not expose it to untrusted networks.

CWE(s)
CWE-20CWE-248

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
T1036.001 Invalid Code Signature Stealth
Adversaries may attempt to mimic features of valid code signatures to increase the chance of deceiving a user, analyst, or tool.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-30359Same product: Webpack.Js Webpack-Dev-Server
CVE-2026-6402Same product: Webpack.Js Webpack-Dev-Server
CVE-2026-14620Same product: Webpack.Js Webpack-Dev-Server
CVE-2025-30360Same product: Webpack.Js Webpack-Dev-Server
CVE-2026-9595Same product: Webpack.Js Webpack-Dev-Server
CVE-2026-50328Shared CWE-20, CWE-248
CVE-2026-25128Shared CWE-20, CWE-248
CVE-2026-73418Shared CWE-20, CWE-248
CVE-2026-45676Shared CWE-20, CWE-248
CVE-2025-47281Shared CWE-20, CWE-248

Affected Assets

webpack.js
webpack-dev-server
≤ 5.2.6

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover missing input validation through analysis or test cases.

SI-10 Information Input Validation good match

SI-10 directly requires validity checks on information inputs, structurally preventing improper or missing validation.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented development standards and tools can embed input-validation practices into the engineering process.

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles include robust exception management to keep the system in a defined state.

SC-24 Fail in Known State partial match

Fail-in-known-state reduces the impact when an uncaught exception occurs by preserving a safe condition.

SI-11 Error Handling partial match

Error handling requirements force structured catching and response to exceptions instead of allowing them to propagate uncaught.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require and enforce input validation during development.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

A.8.25 Secure development life cycle partial match
prevents

Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.

A.8.26 Application security requirements partial match
prevents

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

A.8.28 Secure coding partial match
prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

A.8.7 Protection against malware none match
none

Regular automated validation of system software and data content, combined with scanning of all inbound files, enforces input validation at the boundary before untrusted content is processed.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

RHEL 8 (1 rule)
  • V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20

References