CVE-2026-11856

Published: Jul 3, 2026Modified: Jul 7, 2026

9.8

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitability: 3.9 / Impact: 5.9

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

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`.

Affected (1)

Products: Haxx: Curl

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Haxx Curl	From 7.10.6 to 8.21.0

Related CWEs

Authentication Bypass by Capture-replay

A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).

References (4)

https://curl.se/docs/CVE-2026-11856.html

Source: 2499f714-1537-4658-8207-48ae4bb9eae9

PatchVendor Advisory

https://curl.se/docs/CVE-2026-11856.json

Source: 2499f714-1537-4658-8207-48ae4bb9eae9

Vendor Advisory

https://hackerone.com/reports/3793260

Source: 2499f714-1537-4658-8207-48ae4bb9eae9

ExploitIssue TrackingThird Party Advisory

https://hackerone.com/reports/3793260

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

ExploitIssue TrackingThird Party Advisory

Timeline

No history available yet.