GHSA-3c8v-cfp5-9885 CVE-2026-34776

Electron: Out-of-bounds read in second-instance IPC on macOS and Linux

Medium npm

Severity: 5.3 / 10; Medium · CVSS 3.1
Exploit chance (EPSS): 0.22%; Chance of exploitation in the next 30 days. Higher than 12.96% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-125 Out-of-bounds Read
Fix: 38.8.6; Upgrade electron to this version or later

Description

Impact

On macOS and Linux, apps that call app.requestSingleInstanceLock() were vulnerable to an out-of-bounds heap read when parsing a crafted second-instance message. Leaked memory could be delivered to the app's second-instance event handler.

This issue is limited to processes running as the same user as the Electron app.

Apps that do not call app.requestSingleInstanceLock() are not affected. Windows is not affected by this issue.

Workarounds

There are no app side workarounds, developers must update to a patched version of Electron.

Fixed Versions

41.0.0
40.8.1
39.8.1
38.8.6

For more information

If there are any questions or comments about this advisory, please email security@electronjs.org

Affected versions

npm

Package	Vulnerable	Fixed in
electron	`< 38.8.6`	`38.8.6`
electron	`>= 39.0.0-alpha.1, < 39.8.1`	`39.8.1`
electron	`>= 40.0.0-alpha.1, < 40.8.1`	`40.8.1`
electron	`>= 41.0.0-alpha.1, < 41.0.0`	`41.0.0`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

electron npm → `38.8.6`

npm

npm install electron@38.8.6

yarn

yarn add electron@38.8.6

pnpm

pnpm add electron@38.8.6

Severity breakdown

CVSS 3.1 5.3

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

Attack vector: Local
Attack complexity: High
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: Low

Weakness

CWE-125: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How to prevent it

Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.
Architecture and Design: Use a language that provides appropriate memory abstractions.

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-34776

Packages

github.com/electron/electron

Timeline

Apr 3, 2026 Published
Jul 24, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-qqvq-6xgj-jw8g Electron affected by libvpx's heap buffer overflow in vp8 encoding	High Known exploited	Also affects electron
GHSA-j7hp-h8jx-5ppr libwebp: OOB write in BuildHuffmanTable	High Known exploited	Also affects electron
GHSA-995f-9x5r-2rcj Heap buffer overflow in GPU	Critical Known exploited	Also affects electron
GHSA-jr5w-w6x2-84p9 Electron: Mitigation for compromised eMudhra intermediate certificates	High	Also affects electron
GHSA-h3v5-h239-pg29 Electron: Off-screen rendering on macOS trusts GPU-supplied frame geometry	Low	Also affects electron
GHSA-3qxv-5xgr-q7w9 Electron: Frame subscription trusts GPU-supplied frame geometry	Low	Also affects electron
GHSA-997q-gvvc-jwmx Electron: openExternal permission requests can be attributed to the wrong origin	Medium	Also affects electron
GHSA-fw47-9c62-h3vw Electron: HID and USB permission checks can be attributed to the wrong origin	Medium	Also affects electron

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