---
title: "CVE-2026-54257: Electron: Buffer performs incorrect byte length calculations resulting in heap buffer under/overflow"
url: https://erroneo.us/security/cve/CVE-2026-54257/
description: "CVE-2026-54257 (electron (npm)): Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. From 42.3.1 until…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-23
date_modified: 2026-07-20
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-54257"
kev: false
cvss: 9.3
epss: 0.00428
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-54257: Electron: Buffer performs incorrect byte length calculations resulting in heap buffer under/overflow

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 36: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 36% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes electron (npm) >= 42.3.1, < 42.3.3, fixed in 42.3.3 . Check your lockfile, including transitive dependencies.

## What it is

Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. From 42.3.1 until 42.3.3, Buffer performs incorrect byte length calculations resulting in heap buffer under/overflow. Most apps will crash and some may perform incorrect buffer allocations in the Node.js Buffer API resulting in unexpected truncation or allocation. This vulnerability is fixed in 42.3.3.

## Affected packages

- npm `electron` >= 42.3.1, < 42.3.3 → fixed: 42.3.3

## Affected products (CVE record)

- electron electron: >= 42.3.1, < 42.3.3

## Severity

- GitHub_M CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.43% probability of exploitation activity in the next 30 days; percentile 36.

## Sources

- [GitHub Advisory GHSA-q6m5-f73j-m9mc](https://github.com/advisories/GHSA-q6m5-f73j-m9mc)
- [CVE.org record CVE-2026-54257](https://www.cve.org/CVERecord?id=CVE-2026-54257)
- [NVD entry CVE-2026-54257](https://nvd.nist.gov/vuln/detail/CVE-2026-54257)
- [github.com](https://github.com/electron/electron/security/advisories/GHSA-q6m5-f73j-m9mc)

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Source page: https://erroneo.us/security/cve/CVE-2026-54257/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt