CVE-2026-34767: Electron HTTP Response Header Injection Vulnerability

MODERATE
Advisory Identifier: GHSA-4p4r-m79c-wq3v
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CVSS 5.9
CWE-113 CWE-74
Published
Advisory Summary

CVE-2026-34767 is a MODERATE (CVSS 5.9) http response header injection vulnerability (CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')) affecting Electron libraries in the npm ecosystem. The issue involves http response header injection in custom protocol handlers and webrequest. Remediation is available by upgrading affected packages to version 38.8.6, 39.8.3, 40.8.3, 41.0.3.

CVE-2026-34767 at a Glance

CVE Identifier CVE-2026-34767
GHSA Identifier GHSA-4p4r-m79c-wq3v
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
Affected Product Electron
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-34767

To remediate this vulnerability, upgrade all affected Electron dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

electron fixed: 38.8.6 
npm install electron@38.8.6
electron fixed: 39.8.3 
npm install electron@39.8.3
electron fixed: 40.8.3 
npm install electron@40.8.3
electron fixed: 41.0.3 
npm install electron@41.0.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls electron

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-34767, inspect your project dependencies using npm:

npm ls electron

Analyze the terminal output to locate any version of Electron in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 38.8.6), your application is affected.

Note: The npm ls electron command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting'), where the product receives data from an http agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes cr and lf characters before the data is included in outgoing http headers. In Electron, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact Apps that register custom protocol handlers via `protocol.handle()` / `protocol.registerSchemesAsPrivileged()` or modify response headers via `webRequest.onHeadersReceived` may be vulnerable to HTTP response header injection if attacker-controlled input is reflected into a response header name or value. An attacker who can influence a header value may be able to inject additional response headers, affecting cookies, content security policy, or cross-origin access controls. Apps that do not reflect external input into response headers are not affected. ### Workarounds Validate or sanitize any untrusted input before including it in a response header name or value. ### Fixed Versions * `41.0.3` * `40.8.3` * `39.8.3` * `38.8.6` ### For more information If there are any questions or comments about this advisory, send an email to [security@electronjs.org](mailto:security@electronjs.org)

CVE-2026-34767 Affected Electron Versions

4 component(s)
Fixed Versions:
38.8.639.8.340.8.341.0.3
Product / Package Ecosystem Affected Versions Fixed Version
electron
npm/electron
npm
< 38.8.6
38.8.6
electron
npm/electron
npm
≥ 39.0.0-alpha.1
< 39.8.3
39.8.3
electron
npm/electron
npm
≥ 40.0.0-alpha.1
< 40.8.3
40.8.3
electron
npm/electron
npm
≥ 41.0.0-alpha.1
< 41.0.3
41.0.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/electron/electron/security/advisories/GHSA-4p4r-m79c-wq3v
NVD — CVE-2026-34767 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34767
Electron Source Repository REPOSITORY
https://github.com/electron/electron

Frequently Asked Questions

What is CVE-2026-34767?
CVE-2026-34767 is a security vulnerability in Electron involving HTTP Response Header Injection in custom protocol handlers and webRequest under CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting').
Which Electron versions are affected?
Affected versions include releases prior to 38.8.6, 39.8.3, 40.8.3, 41.0.3 across affected packages: electron.
What version fixes CVE-2026-34767?
Upgrading to 38.8.6, 39.8.3, 40.8.3, 41.0.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is electron affected?
Yes, electron is affected in releases prior to 38.8.6, 39.8.3, 40.8.3, 41.0.3. Upgrade your dependency to 38.8.6, 39.8.3, 40.8.3, 41.0.3 or later.
What is the CVSS score of CVE-2026-34767?
CVE-2026-34767 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N.
What CWE is associated with CVE-2026-34767?
CVE-2026-34767 is classified under CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') (The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.).
How can I check npm dependencies for CVE-2026-34767?
Run the dependency tree command: 'npm ls electron'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4p4r-m79c-wq3v",
  "modified" : "2026-04-06T23:10:30Z",
  "published" : "2026-04-03T02:37:24Z",
  "aliases" : [ "CVE-2026-34767" ],
  "summary" : "Electron: HTTP Response Header Injection in custom protocol handlers and webRequest",
  "details" : "### Impact\nApps that register custom protocol handlers via `protocol.handle()` / `protocol.registerSchemesAsPrivileged()` or modify response headers via `webRequest.onHeadersReceived` may be vulnerable to HTTP response header injection if attacker-controlled input is reflected into a response header name or value.\n\nAn attacker who can influence a header value may be able to inject additional response headers, affecting cookies, content security policy, or cross-origin access controls.\n\nApps that do not reflect external input into response headers are not affected.\n\n### Workarounds\nValidate or sanitize any untrusted input before including it in a response header name or value.\n\n### Fixed Versions\n* `41.0.3`\n* `40.8.3`\n* `39.8.3`\n* `38.8.6`\n\n### For more information\nIf there are any questions or comments about this advisory, send an email to [security@electronjs.org](mailto:security@electronjs.org)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "electron"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "38.8.6"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "electron"
    },
    "ranges" : [ {
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      "events" : [ {
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      }, {
        "fixed" : "39.8.3"
      } ]
    } ]
  }, {
    "package" : {
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      "name" : "electron"
    },
    "ranges" : [ {
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      }, {
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      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "electron"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "41.0.0-alpha.1"
      }, {
        "fixed" : "41.0.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/electron/electron/security/advisories/GHSA-4p4r-m79c-wq3v"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34767"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/electron/electron"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-113", "CWE-74" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-03T02:37:24Z",
    "nvd_published_at" : "2026-04-04T00:16:17Z"
  }
}