CVE-2026-34778: Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS

Q: How do I fix CVE-2026-34778?

electron: upgrade to 38.8.6, 39.8.1, 40.8.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-34778 being exploited?

CVE-2026-34778 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-34778 affect?

CVE-2026-34778 affects electron. Severity is medium (CVSS 5.9). 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 I

Q: How urgent is CVE-2026-34778?

Priority 21/100. No elevated risk signals yet.

Routine

MEDIUM 5.9UPGRADE

CVE-2026-34778 is a medium-severity flaw (CVSS 5.9) affecting electron. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.1% (top 98%)
CISA exploited list	No
Weakness	CWE-290, CWE-345
Published	2026-04-04
Last modified	2026-07-24

Publisher (CNA): GitHub, Inc. · Vendor: electronjs

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-04 00:16 UTCPublished CVE record published
2026-07-24 22:10 UTCUpdated Record last modified

electronjs electron UPGRADE

Affected: < 38.8.6 · >= 39.0.0 and < 39.8.1 · >= 40.0.0 and < 40.8.1 · 41.0.0 alpha1 · 41.0.0 alpha2 · 41.0.0 alpha3 · 41.0.0 alpha4 · 41.0.0 alpha5

Fixed in: 38.8.6, 39.8.1, 40.8.1

Safe to downgrade to: a release before 39.0.0

1. Check installed version

npm ls electron

2. UPGRADE to 38.8.6

npm install electron@">=38.8.6"

3. If no update is available yet, DOWNGRADE to a release before 39.0.0

npm view electron versions npm install electron@"<39.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-34778?

electron: upgrade to 38.8.6, 39.8.1, 40.8.1. Exact commands for each OS are on this page.

Is CVE-2026-34778 being exploited?

CVE-2026-34778 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-34778 affect?

CVE-2026-34778 affects electron. Severity is medium (CVSS 5.9). 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 I

How urgent is CVE-2026-34778?

Priority 21/100. No elevated risk signals yet.

Software pages

Electron vulnerabilities

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References

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