GHSA-4p4r-m79c-wq3v CVE-2026-34767
Electron: HTTP Response Header Injection in custom protocol handlers and webRequest
- Severity
- 5.9 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.21%
- Chance of exploitation in the next 30 days. Higher than 11.96% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
- CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
- Fix
38.8.6- Upgrade electron to this version or later
Description
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
41.0.340.8.339.8.338.8.6
For more information
If there are any questions or comments about this advisory, send an email to security@electronjs.org
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| electron | < 38.8.6 |
38.8.6 |
| electron | >= 39.0.0-alpha.1, < 39.8.3 |
39.8.3 |
| electron | >= 40.0.0-alpha.1, < 40.8.3 |
40.8.3 |
| electron | >= 41.0.0-alpha.1, < 41.0.3 |
41.0.3 |
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 5.9
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- High
- Availability
- None
Weakness
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 to prevent it
- Implementation: Construct HTTP headers very carefully, avoiding the use of non-validated input data.
- 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. If an input does not strictly conform to specifications, reject it or transform it into something that conforms. 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.
- Implementation: Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
How to prevent it
- Requirements: Programming languages and supporting technologies might be chosen which are not subject to these issues.
- Implementation: Utilize an appropriate mix of allowlist and denylist parsing to filter control-plane syntax from all input.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
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