CVE-2026-6402
Webpack.Js Webpack-Dev-Server ≤ 5.2.4
Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:NSummary
CVE-2026-6402 is a medium-severity Exposed Dangerous Method or Function (CWE-749) 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 12th 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 AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-29404
Vulnerability Data
webpack-dev-server versions up to and including 5.2.3 are vulnerable to cross-origin source code exposure when serving over a non-potentially trustworthy origin such as plain HTTP. The previous fix relied on the Sec-Fetch-Mode and Sec-Fetch-Site request headers, which browsers omit for…
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non-trustworthy origins, allowing a malicious site to load the bundled source as a script and read it across origins. Impact: an attacker controlling a website visited by a developer running webpack-dev-server can recover the application source code when the dev server runs over HTTP at a guessable host and port. Chromium based browsers from Chrome 142 onward are not affected due to local network access restrictions. Upgrade to webpack-dev-server 5.2.4 or later, which sets Cross-Origin-Resource-Policy: same-origin on responses.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 4 hardening rules · 2 OS baselines
V8.2.1
Mitigating Controls (NIST 800-53 r5) AI
Access enforcement directly stops unauthorized callers from invoking dangerous API methods or functions.
Least privilege restricts which users or processes may reach dangerous methods, limiting exposure.
Least functionality removes or disables non-essential dangerous methods from the exposed interface altogether.
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.
Enforcing least-privilege authorization directly prevents unrestricted dangerous API methods.
Secure SDLC practices stop developers from exposing dangerous functions in the first place.
Vulnerability identification processes will surface exposed dangerous methods during assessment.
Logical access controls at the network/environment layer can limit reachability of exposed functions.
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.
Security testing can detect exposed dangerous functions, but does not prevent their initial introduction.
Restricting privileged utility programs reduces exposure of dangerous functions, but does not eliminate the underlying weakness.
Privileged access rights limit who can invoke dangerous methods, but do not address whether the method itself should exist.
Secure development life cycle requires removal or protection of dangerous APIs during design and coding.
Application security requirements can mandate that dangerous methods are not exposed in interfaces.
Secure architecture principles discourage exposing dangerous functions, but do not guarantee their absence.
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).
Ubuntu 22.04 (3 rules)
- V-260559 Ubuntu 22.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-749
- V-260529 Ubuntu 22.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements. prevents CWE-749
- V-260557 Ubuntu 22.04 LTS must be configured to use AppArmor. prevents CWE-749
Ubuntu 24.04 (1 rule)
- V-270748 Ubuntu 24.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-749