| Name | CVE-2026-11856 |
| 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`. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|
| curl (PTS) | bullseye | 7.74.0-1.3+deb11u13 | vulnerable |
| bullseye (security) | 7.74.0-1.3+deb11u16 | vulnerable |
| bookworm | 7.88.1-10+deb12u15 | vulnerable |
| bookworm (security) | 7.88.1-10+deb12u5 | vulnerable |
| trixie | 8.14.1-2+deb13u4 | vulnerable |
| forky | 8.20.0-5 | vulnerable |
| sid | 8.21.0-2 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|
| curl | source | (unstable) | 8.21.0~rc3-1 | | | |
Notes
[trixie] - curl <no-dsa> (Minor issue)
[bookworm] - curl <postponed> (Minor issue; needs Digest auth + libcurl handle reuse across origins)
[bullseye] - curl <postponed> (Minor issue; needs Digest auth + libcurl handle reuse across origins)
https://curl.se/docs/CVE-2026-11856.html
Introduced with: https://github.com/curl/curl/commit/334d78cd18a7310144383929bdcef34ffbf6159b (curl-7_10_6)
Fixed by: https://github.com/curl/curl/commit/5c6b4880357ab3e72967c1c45cae0f96ffabc535 (rc-8_21_0-3, curl-8_21_0)