Description
When a libcurl-based application performs transfers via `SCP://` or `SFTP://`
and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an
untrusted server. This vulnerability occurs when a server presents a host key
type that does not match the specific key type already recorded for that host
in the `known_hosts` file. Instead of rejecting the mismatch, the callback
mechanism fails to properly enforce the restriction, allowing the connection
to succeed without warning and risking a potential man-in-the-middle attack.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| curl | curl | 7.69.0 – < 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~rc2-1 | — |
| 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 | 8.18.0-1ubuntu2.2 | — |
| Ubuntu 25.10 | curl | 8.14.1-2ubuntu1.4 | — |
| Ubuntu 24.04 LTS | curl | 8.5.0-2ubuntu10.10 | — |
| Ubuntu 22.04 LTS | curl | 7.81.0-1ubuntu1.25 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | curl +3 | 8.12.1-4.el10_2.3 | RHSA-2026:55450 |
| RHEL 9 | curl +4 | 7.76.1-40.el9_8.5 | RHSA-2026:55439 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | curl +3 | 8.12.1-1.el10_0.10 | RHSA-2026:72506 |
| Red Hat Hardened Images 1 | curl +3 | 8.21.0-0.1.hum1 | RHSA-2026:29017 |
| Red Hat Hardened Images 1 | rust +18 | 1.96.1-1.hum1 | RHSA-2026:34975 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 9 | curl +4 | 7.76.1-40.el9_8.5 | ALSA-2026:55439 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 9 | curl | 7.76.1-40.el9_8.5 | RLSA-2026:55439 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | curl | 8.14.1-150700.7.20.1 | SUSE-SU-2026:2925-1 |
| SLES 15 SP6 | curl | 8.14.1-150600.4.46.1 | 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 | 8.0.1-11.126.1 | SUSE-SU-2026:3814-1 |
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-2026:2926-1 |
| 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 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | curl +3 | 8.12.1-4.el10_2.4 | ELSA-2026-55450 |
| Oracle Linux 9 | curl +4 | 7.76.1-40.el9_8.5 | ELSA-2026-55439 |
Advisories 23
- WID-SEC-2026-2052 cURL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2026
- ALSA-2026:55439 Important: curl security update AlmaLinux Security Advisories · Oct 29, 2026
- NCSC-2026-0441 Kwetsbaarheden verholpen in Oracle MySQL NCSC-NL (Netherlands) · Oct 21, 2026
- WID-SEC-2026-4081 Oracle MySQL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 20, 2026
- RHSA-2026:34975 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:29017 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:72506 Red Hat Security Advisory: curl security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:55450 Red Hat Security Advisory: curl security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- RHSA-2026:55439 Red Hat Security Advisory: curl security update Red Hat Security Advisories (RHSA) · Oct 16, 2026
- ALAS2023-2026-2132 Moderate: curl security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 14, 2026
- SUSE-SU-2026:3814-1 Security update for curl SUSE / openSUSE Security Updates · Aug 31, 2026
- RLSA-2026:55439 Important: curl security update Rocky Linux Security Advisories · Aug 17, 2026
- ELSA-2026-55450 Important: curl security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
- ELSA-2026-55439 Important: curl security update (Oracle Linux 9) 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-2026:2925-1 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-2026:22553-1 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