Description
When a user invokes curl using a schemeless URL combined with
`--proto-default` sftp (or scp), a disconnect occurs between the tool layer
and libcurl. The tool layer incorrectly infers the URL scheme, which
erroneously bypasses the initialization of critical SSH security options like
CURLOPT_SSH_HOST_PUBLIC_KEY_SHA256 and CURLOPT_SSH_KNOWNHOSTS. Conversely, the
libcurl runtime successfully honors CURLOPT_DEFAULT_PROTOCOL and establishes
the connection via SFTP/SCP as specified. Because the tool layer skipped the
security configuration, these SSH host verification options are silently
omitted, causing curl to connect to an unverified SSH remote host without
throwing an error.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| curl | curl | 7.81.0 – < 8.14.2, 8.15.0 – < 8.16.1, 8.17.0 – < 8.20.1, 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.… | 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 | 8.21.0~rc3-1 | — |
| Debian 13 | curl | No fix yet | — |
| Debian 12 | curl | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | curl | 8.18.0-1ubuntu2.3 | — |
| Ubuntu 25.10 | curl | 8.14.1-2ubuntu1.5 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | curl +3 | 8.12.1-4.el10_2.3 | RHSA-2026:55450 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | curl | 8.14.1-150700.7.20.1 | SUSE-SU-2026:5068-1, SUSE-SU-2026:2925-1 |
| SLES 15 SP6 | curl | 8.14.1-150600.4.46.1 | SUSE-SU-2026:5069-1, SUSE-SU-2026:2926-1 |
| SLES 15 SP5 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
| SLES 15 SP4 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
| SLES 12 SP5 | curl | 8.0.1-11.134.1 | SUSE-SU-2026:5071-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | curl +1 | 8.14.1-160000.8.1 | SUSE-SU-2026:22582-1 |
| SLES for SAP 15 SP6 | curl | 8.14.1-150600.4.46.1 | SUSE-SU-2026:5069-1, SUSE-SU-2026:2926-1 |
| SLES 16.0 | curl +1 | 8.14.1-160000.8.1 | SUSE-SU-2026:22582-1 |
| SLE Micro 6.2 | curl | 8.14.1-160000.8.1 | SUSE-SU-2026:22553-1 |
| SLE Micro 6.1 | curl | 8.14.1-slfo.1.1_8.1 | SUSE-SU-2026:22889-1 |
| SLE Micro 6.0 | curl | 8.14.1-7.1 | SUSE-SU-2026:22709-1 |
| SLE Micro 5.5 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
| SLE Micro 5.4 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
| SLE Micro 5.3 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
| SLE HPC 15 SP5 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
| SLE HPC 15 SP4 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
| SUSE Linux Enterprise Installer Updates 15 SP5 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
| SUSE Linux Enterprise Installer Updates 15 SP4 | curl | 8.14.1-150400.5.86.1 | SUSE-SU-2026:3043-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | curl | 8.21.0-1.1 | openSUSE-SU-2026:11230-1 |
| openSUSE Leap 16.0 | curl | 8.14.1-160000.8.1 | openSUSE-SU-2026:21272-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | curl | 8.21.0-r0 | — |
| Alpine v3.23 | curl | 8.22.0-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | curl +4 | 8.21.0-5.amzn2023.0.1 | ALAS2023-2026-2132 |
| Amazon Linux 2 | curl +2 | 8.3.0-1.amzn2.0.13 | ALAS2-2026-3953 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | curl | 8.11.1-10 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | curl +3 | 8.12.1-4.el10_2.4 | ELSA-2026-55450 |
Advisories 17
- WID-SEC-2026-2052 cURL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- SUSE-SU-2026:5069-1 Security update for curl SUSE / openSUSE Security Updates · Nov 3, 2026
- SUSE-SU-2026:5068-1 Security update for curl SUSE / openSUSE Security Updates · Nov 3, 2026
- SUSE-SU-2026:5071-1 Security update for curl SUSE / openSUSE Security Updates · Nov 3, 2026
- RHSA-2026:55450 Red Hat Security Advisory: curl security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- ALAS2-2026-3953 Important: curl security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 28, 2026
- ALAS2023-2026-2132 Moderate: curl security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 14, 2026
- ELSA-2026-55450 Important: curl security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
- SUSE-SU-2026:22889-1 Security update for curl SUSE / openSUSE Security Updates · Jul 28, 2026
- SUSE-SU-2026:22709-1 Security update for curl SUSE / openSUSE Security Updates · Jul 23, 2026
- SUSE-SU-2026:3043-1 Security update for curl SUSE / openSUSE Security Updates · Jul 16, 2026
- SUSE-SU-2026:22582-1 Security update for curl SUSE / openSUSE Security Updates · Jul 15, 2026
- SUSE-SU-2026:2926-1 Security update for curl SUSE / openSUSE Security Updates · Jul 15, 2026
- SUSE-SU-2026:2925-1 Security update for curl SUSE / openSUSE Security Updates · Jul 15, 2026
- SUSE-SU-2026:22553-1 Security update for curl SUSE / openSUSE Security Updates · Jul 14, 2026
- openSUSE-SU-2026:21272-1 Security update for curl SUSE / openSUSE Security Updates · Jul 11, 2026
- openSUSE-SU-2026:11230-1 curl-8.21.0-1.1 on GA media SUSE / openSUSE Security Updates · Jul 10, 2026