Description
Using libcurl, when a custom `Host:` header is first set for an HTTP request
and a second request is subsequently done using the same *easy handle* but
without the custom `Host:` header set, the second request would use stale
information and pass on cookies meant for the first host in the second
request. Leak them.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| curl | curl | 7.71.0 – < 8.14.2, 8.15.0 – < 8.16.1, 8.17.0 – < 8.20.0, 8.19.0, 8.18.0, 8.17.0, 8.16.0, 8.15.0, 8.14.1, 8.14.0, 8.13.0, 8.12.1, 8.12.0, 8.11.1, 8.11.0, 8.10.1, 8.10.0, 8.9.1, 8.9.0, 8.8.0, 8.7.1, 8.7.0, 8.6.0, 8.5.0, 8.4.0, 8.3.0, 8.2.1, 8.2.0, 8.1.2, 8.1.1, 8.1.0, 8.0.1, 8.0.0, 7.88.1, 7.88.0, 7.… | 8.14.2 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | curl | 8.20.0~rc3-1 | — |
| Debian 13 | curl | 8.14.1-2+deb13u4 | — |
| Debian 12 | curl | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | curl | 8.18.0-1ubuntu2.1 | — |
| Ubuntu 25.10 | curl | 8.14.1-2ubuntu1.3 | — |
| Ubuntu 24.04 LTS | curl | 8.5.0-2ubuntu10.9 | — |
| Ubuntu 22.04 LTS | curl | 7.81.0-1ubuntu1.24 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.2 EUS | curl +3 | 8.12.1-4.el10_2.9 | RHSA-2026:99643 |
| Red Hat Hardened Images 1 | curl +3 | 8.20.0-0.1.hum1 | RHSA-2026:12916 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | curl | 8.14.1-150700.7.23.1 | SUSE-SU-2026:3798-1 |
| SLES 12 SP5 | curl | 8.0.1-11.123.1 | SUSE-SU-2026:2703-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | curl +1 | 8.14.1-160000.6.1 | SUSE-SU-2026:22156-1 |
| SLES 16.0 | curl +1 | 8.14.1-160000.6.1 | SUSE-SU-2026:22156-1 |
| SLE Micro 6.2 | curl | 8.14.1-160000.6.1 | SUSE-SU-2026:22146-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | curl | 8.20.0-1.1 | openSUSE-SU-2026:10674-1 |
| openSUSE Leap 16.0 | curl | 8.14.1-160000.6.1 | openSUSE-SU-2026:20973-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | curl | 8.20.0-r0 | — |
| Alpine v3.23 | curl | 8.20.0-r0 | — |
| Alpine v3.22 | curl | 8.14.1-r4 | — |
| Alpine v3.21 | curl | 8.14.1-r3 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | cmake | 3.30.3-14 | — |
| Azure Linux 3 | curl | 8.11.1-7 | — |
Advisories 13
- RHSA-2026:99643 Red Hat Security Advisory: curl security update Red Hat Security Advisories (RHSA) · Nov 13, 2026
- WID-SEC-2026-1307 cURL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- WID-SEC-2026-2929 Splunk Splunk Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 21, 2026
- ICSA-26-293-05 Hitachi Energy RTU500 Product CISA ICS & IT advisories · Oct 20, 2026
- RHSA-2026:12916 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- VDE-2026-088 METTLER TOLEDO: LabX Standard and Enterprise Report on External Component Analysis - v21.4 CERT@VDE · Sep 10, 2026
- WID-SEC-2026-3167 Hitachi Energy RTU500: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 2, 2026
- SUSE-SU-2026:3798-1 Security update for curl SUSE / openSUSE Security Updates · Aug 27, 2026
- SUSE-SU-2026:2703-1 Security update for curl SUSE / openSUSE Security Updates · Jul 1, 2026
- SUSE-SU-2026:22156-1 Security update for curl SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:20973-1 Security update for curl SUSE / openSUSE Security Updates · Jun 24, 2026
- SUSE-SU-2026:22146-1 Security update for curl SUSE / openSUSE Security Updates · Jun 19, 2026
- openSUSE-SU-2026:10674-1 curl-8.20.0-1.1 on GA media SUSE / openSUSE Security Updates · May 5, 2026