CVE-2026-34773
Electronjs Electron ≤ 38.8.6
Raw vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:NSummary
CVE-2026-34773 is a medium-severity Improper Input Validation (CWE-20) vulnerability in Electronjs Electron. Its CVSS base score is 4.7 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 15th 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.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34773 is a vulnerability in the Electron framework, which enables developers to build cross-platform desktop applications using JavaScript, HTML, and CSS. On Windows systems, versions prior to 38.8.6, 39.8.1, 40.8.1, and 41.0.0 of Electron fail to validate the protocol name passed to the app.setAsDefaultProtocolClient(protocol) method before writing to the Windows registry. This improper input validation (CWE-20 and CWE-74) allows applications that supply untrusted or external input as the protocol name to inadvertently write to arbitrary subkeys under HKCU\Software\Classes\, potentially enabling protocol handler hijacking. Applications using hardcoded protocol names remain unaffected.
Exploitation requires local access to the target system (AV:L) by an attacker with low privileges (PR:L), though it demands high attack complexity (AC:H) due to the need for the vulnerable application to process untrusted input via the affected API. A successful attack grants high integrity impact (I:H) with no confidentiality or availability disruption, allowing the attacker to overwrite or manipulate registry entries for existing protocol handlers. This could redirect user interactions with specific protocols to malicious handlers controlled by the attacker.
The Electron security advisory at https://github.com/electron/electron/security/advisories/GHSA-mwmh-mq4g-g6gr confirms the issue has been addressed in versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0 through proper validation of the protocol name parameter. Security practitioners should urge developers to update Electron dependencies immediately if using the app.setAsDefaultProtocolClient() method with dynamic inputs and audit applications for untrusted protocol handling to mitigate exposure.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-18945
Vulnerability Data
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0, on Windows, app.setAsDefaultProtocolClient(protocol) did not validate the protocol name before writing to the registry. Apps that pass untrusted…
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input as the protocol name may allow an attacker to write to arbitrary subkeys under HKCU\Software\Classes\, potentially hijacking existing protocol handlers. Apps are only affected if they call app.setAsDefaultProtocolClient() with a protocol name derived from external or untrusted input. Apps that use a hardcoded protocol name are not affected. This issue has been patched in versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
V1.2.1V1.2.3V1.2.5V1.2.8
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing input validation through analysis or test cases.
SI-10 directly requires validity checks on information inputs, structurally preventing improper or missing validation.
Requiring documented development standards and tools can embed input-validation practices into the engineering process.
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.
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.
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.
Logging supports detection of injection attempts but does not prevent the weakness.
Monitoring activities can identify active injection attacks after they occur.
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.
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.
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.
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