CVE-2026-34776: Heap Read in Electron Apps
Platform
nodejs
Component
electron
Fixed in
38.8.7
39.0.1
40.0.1
41.0.1
38.8.6
CVE-2026-34776 describes a heap read vulnerability discovered in Electron applications. This flaw allows attackers to potentially leak memory through crafted second-instance messages, impacting applications that utilize app.requestSingleInstanceLock() on macOS and Linux. Affected versions include those prior to Electron 40.8.1 and 38.8.6; a patch is available in these versions.
Impact and Attack Scenarios
The vulnerability stems from an out-of-bounds heap read when Electron applications process specially crafted second-instance messages. This occurs specifically when the application calls app.requestSingleInstanceLock(). Successful exploitation can lead to the leakage of memory contents, potentially exposing sensitive data handled by the application's second-instance event handler. The impact is limited to processes running under the same user account as the Electron application, preventing broader system compromise. While not directly exploitable for remote code execution, the leaked memory could be leveraged for information disclosure or, in certain scenarios, to bypass security controls within the application's context.
Exploitation Context
CVE-2026-34776 was publicly disclosed on April 3, 2026. There is currently no indication of active exploitation campaigns targeting this vulnerability. The vulnerability is not listed on the CISA KEV catalog as of this writing. Public proof-of-concept exploits are not yet widely available, but the nature of the vulnerability suggests that such exploits could be developed relatively easily.
Threat Intelligence
Exploit Status
EPSS
0.01% (3% percentile)
CISA SSVC
CVSS Vector
What do these metrics mean?
- Attack Vector
- Local — attacker needs a local shell or interactive session on the system.
- Attack Complexity
- High — requires a race condition, non-default configuration, or specific circumstances. Harder to exploit reliably.
- Privileges Required
- Low — any valid user account is sufficient. Basic authenticated access required.
- User Interaction
- None — attack is automatic and silent. Victim does nothing: no click, no file open.
- Scope
- Unchanged — impact is limited to the vulnerable component itself.
- Confidentiality
- High — complete confidentiality loss. Attacker can read all data: credentials, keys, personal data.
- Integrity
- None — no integrity impact. Attacker cannot modify data.
- Availability
- Low — partial or intermittent denial of service. Attacker can degrade performance.
Affected Software
Weakness Classification (CWE)
Timeline
- Reserved
- Published
- Modified
- EPSS updated
Mitigation and Workarounds
The primary mitigation for CVE-2026-34776 is to upgrade to a patched version of Electron, specifically version 40.8.1 or later, or 38.8.6 or later. As there are no application-side workarounds, developers must prioritize updating their Electron dependencies. Rollback is not a viable option; reverting to an older, vulnerable version reintroduces the risk. Consider implementing input validation for second-instance messages, though this is not a substitute for patching. Monitor application logs for unusual memory access patterns or crashes that might indicate exploitation attempts.
How to fix
Update to a patched version of Electron, such as 38.8.6, 39.8.1, 40.8.1, or 41.0.0. This update addresses an out-of-bounds read vulnerability in second-instance message handling, preventing potential memory leaks to applications using `app.requestSingleInstanceLock()`.
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Frequently asked questions
What is CVE-2026-34776 — heap read in Electron Apps?
CVE-2026-34776 is a vulnerability affecting Electron applications on macOS and Linux where crafted messages can lead to memory leaks.
Am I affected by CVE-2026-34776 in Electron Apps?
You are affected if you use Electron versions prior to 40.8.1 or 38.8.6 and your application calls app.requestSingleInstanceLock().
How do I fix CVE-2026-34776 in Electron Apps?
Upgrade your Electron application to version 40.8.1 or later, or 38.8.6 or later. There are no application-side workarounds.
Is CVE-2026-34776 being actively exploited?
There is currently no evidence of active exploitation, but the vulnerability is potentially exploitable.
Where can I find the official Electron advisory for CVE-2026-34776?
Refer to the official Electron security advisory for details: [https://github.com/electron/electron/security/advisories/GHSA-xxxx-xxxx-xxxx](https://github.com/electron/electron/security/advisories/GHSA-xxxx-xxxx-xxxx) - Replace with actual advisory URL.
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