CVE-2026-11856

critical · 9.8

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`.

9.8

CVSS

0.7%

EPSS (exploit prob.)

51st

EPSS percentile

2026-07-03

Published

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

Weaknesses

CWE-294

Affected products

Vendor	Product	Affected versions
haxx	curl	>= 7.10.6, < 8.21.0

Check a specific version with /api/v1/cve/match.

References

https://curl.se/docs/CVE-2026-11856.html
https://curl.se/docs/CVE-2026-11856.json
https://hackerone.com/reports/3793260
https://hackerone.com/reports/3793260

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-11856