CVE-2026-3783
OAuth2 Token Leakage via Redirects in curl HTTP Transfers
Publication date: 2026-03-11
Last updated on: 2026-03-12
Assigner: curl
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| haxx | curl | From 7.33.0 (inc) to 8.19.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-522 | The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
[{'type': 'paragraph', 'content': 'CVE-2026-3783 is a medium-severity vulnerability in curl versions 7.33.0 through 8.18.0 involving the leakage of OAuth2 bearer tokens during HTTP(S) redirects.'}, {'type': 'paragraph', 'content': "When a curl transfer uses an OAuth2 bearer token and encounters a redirect to a second URL, curl may inadvertently send the bearer token to the redirected hostname if that hostname is present in the user's .netrc file under the machine or default keywords."}, {'type': 'paragraph', 'content': 'This results in the token being exposed to an unintended host due to insufficiently protected credentials (CWE-522).'}] [1, 2, 3]
How can this vulnerability impact me? :
This vulnerability can lead to the unintended exposure of OAuth2 bearer tokens to unauthorized hosts during HTTP(S) redirects.
If an attacker controls or has access to the redirected hostname listed in the .netrc file, they could receive the bearer token and potentially use it to gain unauthorized access to protected resources or services.
This compromises the confidentiality and security of authentication credentials, increasing the risk of unauthorized access and data breaches.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, users are advised to upgrade curl to version 8.19.0 or later, where the issue has been fixed.
Alternatively, users can apply the patch and rebuild libcurl if they are using it in their applications.
As an additional mitigation, avoid using OAuth2 bearer tokens with HTTP(S) redirects to prevent the token from being leaked to unintended hosts.