Is CVE-2026-34778 in the CISA KEV catalog?

No. CVE-2026-34778 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34778?

CVE-2026-34778 has a CVSS v3 base score of 5.9 (MEDIUM).

What is the EPSS score for CVE-2026-34778?

CVE-2026-34778 has an EPSS score of 0.12% (2th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34778?

Upgrade electron to 40.8.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-34778

MEDIUM

5.9

CVSS v3

NVD

Description

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, a service worker running in a session could spoof reply messages on the internal IPC channel used by webContents.executeJavaScript() and related methods, causing the main-process promise to resolve with attacker-controlled data. Apps are only affected if they have service workers registered and use the result of webContents.executeJavaScript() (or webFrameMain.executeJavaScript()) in security-sensitive decisions. This issue has been patched in versions 38.8.6, 39.8.1, 40.8.1, and 41.0.0.

CWE-290 CWE-345

How to fix

Remediation Available

electronNVD

Affected:>= 40.0.0, < 40.8.1Fixed in:40.8.1CVE-2026-34778derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N

Exploit Intelligence

0.12%probability of exploitation in 30 days

2ndpercentile

Low risk: more likely to be exploited than 2% of all known CVEs.

References

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-290 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-4358	Critical	9.8	97%	KEV	-
CVE-2022-24112	Critical	9.8	96%	KEV	Fix
CVE-2022-23131	Critical	9.1	96%	KEV	-
CVE-2021-29441	High	8.6	74%	-	Fix
CVE-2021-31195	Medium	6.5	74%	-	Fix
CVE-2020-7388	Critical	10.0	70%	-	Fix

Embed a live status badge for CVE-2026-34778

Markdown

[![CVE-2026-34778](https://tridentstack.com/cve/badge/CVE-2026-34778.svg)](https://tridentstack.com/cve/CVE-2026-34778)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-34778"><img src="https://tridentstack.com/cve/badge/CVE-2026-34778.svg" alt="CVE-2026-34778"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-20.