CVE-2026-9079 Details
Description
libcurl had a flaw that when instructed to clear proxy authentication credentials which made it not do so, leaving the old credentials around to get used for subsequent transfers that should not know nor use them.
A credential disclosure vulnerability exists in curl's libcurl component, specifically in versions 8.8.0 prior to 8.21.0. The issue arises within the CURLOPT_PROXYUSERPWD option, which is used to set proxy authentication credentials. When this option is changed or cleared, the old password can persist and be inadvertently sent during subsequent proxy requests, leaking sensitive information.
Users are advised to upgrade curl and libcurl to version 8.21.0 or later. Alternatively, the patch available in the curl GitHub repository can be applied to the current version before rebuilding.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 6, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://hackerone.com/reports/3750295 | CISA-ADP | ExploitIssue TrackingThird Party Advisory |
| https://curl.se/docs/CVE-2026-9079.html | curl | PatchVendor Advisory |
| https://curl.se/docs/CVE-2026-9079.json | curl | Vendor Advisory |
| https://hackerone.com/reports/3750295 | curl | ExploitIssue TrackingThird Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-522 | Insufficiently Protected Credentials | [email protected] |
| CWE-522 | Insufficiently Protected Credentials | curl |
Affected Products
| Product | Versions |
|---|---|
| haxx curl | >= 8.8.0, < 8.21.0 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 15, 2026 | CVE Modified | curl |
| Sep 15, 2026 | CVE Modified | CISA-ADP |
| Jul 7, 2026 | Initial Analysis | [email protected] |
| Jul 6, 2026 | CVE Modified | CISA-ADP |
| Jul 3, 2026 | New CVE Received | curl |