CVE-2026-11856
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.69%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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`.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.69% probability · 51th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-294
- Affected
- haxx/curl
- Source
- 2499f714-1537-4658-8207-48ae4bb9eae9
References
- https://curl.se/docs/CVE-2026-11856.htmlPatch, Vendor Advisory
- https://curl.se/docs/CVE-2026-11856.jsonVendor Advisory
- https://hackerone.com/reports/3793260Exploit, Issue Tracking, Third Party Advisory
- https://hackerone.com/reports/3793260Exploit, Issue Tracking, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.