CVE-2026-11856
Critical
Description
Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with **Digest** authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.
SeverityCritical
CVSS9.8
Exploit probability—
ProductHaxx Curl
PublishedJul 3, 2026
First seenJul 3, 2026
Weakness typeCWE-294CWE-294
How to fix
Update
- haxx curl8.21.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| haxx curl | 7.10.6 ≤ v < 8.21.0 | 8.21.0 |
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