How severe is CVE-2026-70603?

CVE-2026-70603 has a CVSS score of 6/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-70603?

CVE-2026-70603 affects the following packages: electron (npm), electron (npm), electron (npm), electron (npm). Ecosystems affected: npm.

How do I fix CVE-2026-70603?

Update electron to 42.0.0-beta.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-70603 is resolved across your whole dependency graph.

How do I detect CVE-2026-70603 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for electron, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-70603 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-70603 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-70603 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-70603?

CVE-2026-70603 has an EPSS (Exploit Prediction Scoring System) score of 0.1%, placing it in the 2th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-70603?

CVE-2026-70603 is classified as Improper Input Validation (CWE-20), CWE-158 (CWE-158). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-70603 published, and has it been updated?

CVE-2026-70603 was published on August 5, 2026 and was last updated on October 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

CVE-2026-70603 — electron

MEDIUM

CVE-2026-70603 is a medium-severity (CVSS 6) Improper Input Validation vulnerability in electron. A fix is available for electron — see the affected versions and patch details below.

Electron: shell.openPath path validation bypass via embedded null byte

Also known asGHSA-5c9j-mhmv-5xgx

Published

Aug 5, 2026

Updated

Oct 10, 2026

Affected

4 pkgs

Patched

4 / 4

Exploits

None indexed

Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-70603.

EPSS Exploitation Probability

via FIRST.org ↗

0.1%probability of exploitation in next 30 days

Lower Risk-0.01%

Lower risk than most CVEs2th percentile — riskier than 2% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-70603 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

4 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

2Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

electronnpm

7.9Mdownloads / week

Description

Impact

shell.openPath() did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths (for example, checking the file extension) before passing them to shell.openPath() could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation.

Apps are only affected if they pass paths derived from untrusted input to shell.openPath() and rely on string-based validation without a filesystem check. Node's fs APIs already reject paths containing null bytes, so apps that call fs.existsSync(), fs.stat(), or similar before shell.openPath() are not affected. Apps that do not call shell.openPath() with untrusted input are not affected.

Workarounds

Reject any path containing a null byte before passing it to shell.openPath():

if (filePath.includes('\0')) throw new Error('invalid path');

Fixed Versions

42.0.0-beta.1
41.1.1
40.9.0
39.8.6

For more information

If you have any questions or comments about this advisory, email us at [email protected]

Affected Packages

4 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`electron`	≥ 42.0.0-alpha.1&&< 42.0.0-beta.1	42.0.0-beta.1`npm install electron@42.0.0-beta.1`
📦npm	`electron`	≥ 41.0.0-alpha.1&&< 41.1.1	41.1.1`npm install electron@41.1.1`
📦npm	`electron`	≥ 40.0.0-alpha.1&&< 40.9.0	40.9.0`npm install electron@40.9.0`
📦npm	`electron`	all versions	39.8.6`npm install electron@39.8.6`

Affected Products

1 product · 10 configurations

Application

electronelectronjs

≥ 41.0.0 && < 41.1.1

1 version

42.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for electron, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update electron to 42.0.0-beta.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-70603 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact `shell.openPath()` did not reject paths containing embedded null bytes. Apps that perform string-only validation of file paths (for example, checking the file extension) before passing them to `shell.openPath()` could be bypassed, allowing an attacker-controlled path to open a different file than the one that passed validation. Apps are only affected if they pass paths derived from untrusted input to `shell.openPath()` and rely on string-based validation without a filesystem check. Node's `fs` APIs already reject paths containing null bytes, so apps that call `fs.existsSync()`, `fs