CVE-2026-6253
Fixed in a distro release EPSS <1%CVSS 5.9
curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the second proxy uses no credentials 4. while using the first proxy (using say `http://`), curl is asked to follow a redirect to a URL using another scheme (say `https://`), accessed using a second, different, proxy
Products: curl
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux 10 | curl | 8.12.1-4.el10_2.7 |
| AlmaLinux 10 | libcurl | 8.12.1-4.el10_2.7 |
| AlmaLinux 10 | libcurl-devel | 8.12.1-4.el10_2.7 |
| AlmaLinux 10 | libcurl-minimal | 8.12.1-4.el10_2.7 |
| Alpine 3.21 | curl | 8.14.1-r3 |
| Alpine 3.22 | curl | 8.14.1-r4 |
| Alpine 3.23 | curl | 8.20.0-r0 |
| Alpine 3.24 | curl | 8.20.0-r0 |
| Chainguard | libcurl4 | no fix |
| Debian 12 | curl | no fix |
| Debian 13 | curl | 8.14.1-2+deb13u4 |
| Debian 14 | curl | 8.20.0~rc3-1 |
| Red Hat Enterprise Linux 10.2 | curl | 0:8.12.1-4.el10_2.7 |
| Red Hat Enterprise Linux 10.2 | curl-debuginfo | 0:8.12.1-4.el10_2.7 |
| Red Hat Enterprise Linux 10.2 | curl-debugsource | 0:8.12.1-4.el10_2.7 |
| Red Hat Enterprise Linux 10.2 | libcurl | 0:8.12.1-4.el10_2.7 |
| Red Hat Enterprise Linux 10.2 | libcurl-debuginfo | 0:8.12.1-4.el10_2.7 |
| Red Hat Enterprise Linux 10.2 | libcurl-devel | 0:8.12.1-4.el10_2.7 |
| Red Hat Enterprise Linux 10.2 | libcurl-minimal | 0:8.12.1-4.el10_2.7 |
| Red Hat Enterprise Linux 10.2 | libcurl-minimal-debuginfo | 0:8.12.1-4.el10_2.7 |
| Red Hat hummingbird 1 | curl | 0:8.20.0-0.1.hum1 |
| Red Hat hummingbird 1 | libcurl | 0:8.20.0-0.1.hum1 |
| Red Hat hummingbird 1 | libcurl-devel | 0:8.20.0-0.1.hum1 |
| Red Hat hummingbird 1 | libcurl-minimal | 0:8.20.0-0.1.hum1 |
| Rocky Linux 10 | curl | 0:8.12.1-4.el10_2.7 |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | curl | 8.14.1-150700.7.23.1 |
| SUSE Linux Enterprise Server 16.0 | curl | 8.14.1-160000.6.1 |
| SUSE Linux Enterprise Server 16.0 | curl-mini | 8.14.1-160000.6.1 |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | curl | 8.0.1-11.123.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | curl | 8.14.1-160000.6.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | curl-mini | 8.14.1-160000.6.1 |
| SUSE Linux Micro 6.2 | curl | 8.14.1-160000.6.1 |
| Ubuntu 22.04 LTS | curl | 7.81.0-1ubuntu1.24 |
| Ubuntu 24.04 LTS | curl | 8.5.0-2ubuntu10.9 |
| Ubuntu 25.10 | curl | 8.14.1-2ubuntu1.3 |
| Ubuntu 26.04 LTS | curl | 8.18.0-1ubuntu2.1 |
| Ubuntu Pro 14.04 LTS | curl | no fix |
| Ubuntu Pro 16.04 LTS | curl | no fix |
| Ubuntu Pro 18.04 LTS | curl | no fix |
| Ubuntu Pro 20.04 LTS | curl | no fix |
| Wolfi | libcurl4 | no fix |
| openSUSE Leap 16.0 | curl | 8.14.1-160000.6.1 |
| openSUSE Tumbleweed | curl | 8.20.0-1.1 |