Security Digest · Vulnerability record
CVE-2026-54257: Electron: Buffer performs incorrect byte length calculations resulting in heap buffer under/overflow
Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS.
CVSS 9.3 Critical EPSS 0.4% · p36
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- 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.
From the GitHub advisory
Impact Most apps will crash and some may perform incorrect buffer allocations in the Node.js Buffer API resulting in unexpected truncation or allocation.
Workarounds No workarounds. Do not use these impacted Electron releases
Fixed Versions 42.3.3
For more information If you have any questions or comments about this advisory, email us at security@electronjs.org
Weakness type: CWE-120.
Product: electron (npm) · Assigned by: GitHub_M · Published: 2026-06-23
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | electron | >= 42.3.1, < 42.3.3 | 42.3.3 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| electron | electron | >= 42.3.1, < 42.3.3 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 4.0 | 9.3 Critical | 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 | 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 |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: none
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- 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.
Timeline
- — GitHub-reviewed advisory GHSA-q6m5-f73j-m9mc published (critical)
- — CVE record last updated
- — CVE record published by GitHub_M
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-q6m5-f73j-m9mc github.com
- CVE.org record CVE-2026-54257 cve.org
- NVD entry CVE-2026-54257 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com